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PSpice® Advanced Analysis User's Guide

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1. 0 0c cece eee ee 30 Creating new Advanced Analysis ready designs lille 31 Using the design variables table 0 ccc tee eee 33 July 2005 3 Product Version 10 5 PSpice Advanced Analysis Users Guide Modifying existing designs for Advanced Analysis 0 00 cece eee eee 35 Example aa do nah a hc Si a he uit cg rare E cat NAE E di Qu D d ge area an DE 36 Selecting a parameterized component 0c ces 36 Setting a parameter value 61 eens 37 Using the design variables table 225 o Es Dee ese ee C RRO ees 38 EOLDOWOL USCIS 6252 oh eas pandas hee Aus aUud bab ate Sra dor Lad oe Kc A Sch duco 39 Legacy PSpice optimizations slllllle ee 39 3 SISTEMAS NETTE TTD IET 41 Imtis ehapt r u c Sat ma nee ave a a e dosis cd n lan AC MIA DUC ara AD C El d 41 Sensitivity overview acisenotcetirer tuos e BU PEU Ee teo CE a p E ap fo o ede etaed Sp 41 Sensitivity strategy 2 5 5d oO ELE eet RE ae DERI ad eb kak Aes fuss 43 liz In bz lazio RP Be ts Bybee EPOR Pes TON ERREUR RENE oe 43 MVOERTIOW cce ed essere em vaut d rpte a E E Bids a itu s e E 44 Sensitivity PFOCCOUEE 224 s RR Yo ie Bava RB du p EVA ORE ERG eri deal aa th ie dr e ae 44 Setting up the circuit in the schematic editor lllllssss 44 Setting up Sensitivity in Advanced Analysis 0 0c eee ees 45 R nning Sensitivity co Be teks Ae eth orbe edis dod
2. Grey bars indicate that limits are not available for the parameters or Help press F1 Right click and select Parameter Descriptions to decipher the parameter acronyms Printing results Click amp Or From the File menu select Print 150 PSpice Advanced Analysis Users Guide Product Version 10 5 Example Configuring Smoke Selecting another derating option The default derating option uses 100 derating factors also called No Derating We ll now run the circuit with standard derating and examine the results Selecting standard derating 1 Right click and from the pop up menu select Derating 2 Select Standard Derating from the pull right menu m Average Values m RMS Values m Peak Values Temperature Parameters Only Parameter Descriptions Find in Design Derating b v No Derating Standard Derating Copy Custom Derating Files 3 Click I on the top toolbar to run a new Smoke analysis New results appear PSpice Advanced Analysis Users Guide 151 Chapter 5 Smoke Product Version 10 5 The red bar indicates that Q1 s VCE parameter is stressed Standard derating factors Standard Derating Component Q1 s VCE parameter is used in the calculations appears in the title stressed to 136 percent of its safe operating limit ojx lalx amp vts is rf amp SCHEMATICI PSpice Advanced Analysis Smoke File Edit View Run Analysis Window Help
3. Use the Random engine to search for alternate starting points Go to the Error Graph history and copy the best Random engine result to the Nth run the end Then switch to the Modified LSQ or LSQ engine to pinpoint the final answer Use the Troubleshoot in PSpice feature to check the shapes of the traces and make sure they are appropriate for the desired measurement right click on a measurement row and select the Troubleshoot command from the pop up menu For example do the traces show that the filter still looks like a bandpass Try changing the simulation settings to increase the range of frequencies Or Restrict the parameter ranges in the Optimizer Parameters table to prevent the problem Increase number of iterations in the Optimizer engine settings tab from the Edit menu select Profile Settings and click the Optimizer tab PSpice Advanced Analysis Users Guide Product Version 10 5 Problem Analysis fails Possible cause Common problems and solutions Solution Smoke analysis fails Output window displays the following error for smoke parameters Data not found for Smoke test Please verify Save Data and Data Collection options in the simulation profile Monte Carlo analysis takes too long get an evaluation error message Data save start time is not zero or data collection options for voltages currents and power is not set to All The number of runs may be to
4. Table 5 2 Supported derate type Device Category Physical Device RES CAP IND DIODE NPN PNP JFET N CHANNEL P CHANNEL NMESFET PMESFET MOS NMOS PMOS OPAMP ZENER IGBT VARISTOR OCNN OCNPN THYRISTOR POS_REG LED Resistor Capacitor Inductor Diode NPN Bipolar Junction Transistor PNP Bipolar Junction Transistor Junction FET N Channel JFET P Channel JFET N Channel MESFET P Channel MESFET MOSFET N Channel MOSFET P Channel MOSFET Operational Amplifiers Zener Diode Ins Gate Bipolar Transistor Varistor Octo Coupler using PNP transistor Octo Coupler using NPN transistor Thyristor Positive Voltage Regulator Light Emitting Diode PSpice Advanced Analysis Users Guide 171 Chapter 5 Smoke Product Version 10 5 172 PSpice Advanced Analysis Users Guide Monte Carlo In this chapter Monte Carlo overview on page 173 Monte Carlo strategy on page 174 Monte Carlo procedure on page 177 Example on page 188 Monte Carlo overview Note Monte Carlo analysis is available with the following products O PSpice Advanced Optimizer Option O PSpice Advanced Analysis Monte Carlo predicts the behavior of a circuit statistically when part values are varied within their tolerance range Monte Carlo also calculates yield which can be used for mass manufacturing predictions Use Monte Carlo for W Calculating yield based on your specs W Integrating measurements with graphical
5. Glossary weight worst case maximum worst case minimum yield 346 Product Version 10 5 Related to Optimizer In Optimizer we are trying to minimize the error between the calculated measurement value and our goal If one of our goals is more important than another we can emphasize that importance by artificially making that goal s error more noticeable on our error plot If the error is artificially large we ll be focusing on reducing that error and therefore focusing on that goal We make the error stand out by applying a weight to the important goal The weight is a positive integer say 10 that is multiplied by the goal s error which results in a magnified error plot for that goal Related to Sensitivity This is a maximum calculated value for a measurement based on all parameters set to their tolerance limits in the direction that will increase the measurement value Related to Sensitivity This is a minimum calculated value for a measurement based on all parameters set to their tolerance limits in the direction that will decrease the measurement value Related to Monte Carlo Yield is used to estimate the number of usable components or circuits produced during mass manufacturing Yield is a percent calculation based on the number of run results that meet design specifications versus the total number of runs For example a yield of 99 percent indicates that of all the Monte Carlo runs 99 percent of the
6. Mapping frame in the Model Editor For template based PSpice Advanced Analysis Users Guide Product Version 10 5 Template property file models this information is not editable but for non parameterized models you can edit this information A sample of the pre_smoke section is shown below pre_smoke NODE POS PIN NODE NEG NIN NODE VCC PVss NODE VEE NVss NODE GND O TERM POS 1 ERM NEG 2 ERM OUT 3 DERATE TYPE OPAMP The pre smoke section also lists the derate type The DERATE TYPE line specifies the derate type to be used for the model The derate types are defined in the STANDARD DRT file Note To find out more about derate types and derating files see the chapter on Smoke Table A 2 lists the supported DERATE TYPEs Table A 2 Supported derate type DERATE TYPE Part RES CAP IND DIODE NPN PNP JFET N CHANNEL P CHANNEL PSpice Advanced Analysis Users Guide Resistor Capacitor Inductor Diode NPN Bipolar Junction Transistor PNP Bipolar Junction Transistor Junction FET N Channel JFET P Channel JFET 329 Chapter A Property Files Product Version 10 5 Table A 2 Supported derate type DERATE TYPE Part NMESFET N Channel MESFET PMESFET P Channel MESFET MOS MOSFET NMOS N Channel MOSFET PMOS P Channel MOSFET OPAMP Operational Amplifiers ZENER Zener Diode IGBT Ins Gate Bipolar Transi
7. Optimizing a design using measurement specifications This example uses the tutorial version of RFAmp located at lt target directory gt PSpice tutorial capture pspiceaa rfamp The circuit is an RF amplifier with 50 ohm source and load impedances It includes the circuit schematic PSpice simulation profiles and measurements Note For a completed example see target directory gt PSpice Capture_Samples AdvAnIs RFAmp directory The example uses the goals and constraints features in the Modified LSQ engine The engine strives to get as close as possible to the goals while ensuring that the constraints are met When designing an RF circuit there is often a trade off between the bandwidth response and the gain of the circuit In this example we are willing to trade some gain and input and output noise to reach our bandwidth goal Optimizer goal m Increase bandwidth from 150 MHz to 200 MHz Note Enter meg or e6 for MHz when entering these values in the Specifications table Optimizer constraints B Gain of at least 5 dB original value is 9 4 dB m Max noise figure of 5 original value is 4 1 PSpice Advanced Analysis Users Guide 107 Chapter 4 Optimizer Product Version 10 5 m Max output noise of 3 nano volts per root Hz original value is 4 3 nano volts per root Hz Setting up the circuit in the schematic editor 1 In your schematic editor browse to the RFAmp tutorials directory target directory PSpic
8. Product Version 10 5 LSQ engine m There is no convergence of AFCTOL RFCTOL or XCTOL B The present step yields less than twice the predicted decrease m The relative step size is less than or equal to XFTOL PSpice Advanced Analysis Users Guide 281 Chapter 9 Optimization Engines Modified LSQ engine Product Version 10 5 The Modified LSQ engine uses both constrained and unconstrained minimization algorithms which allow it to optimize goals subject to nonlinear constraints The Modified LSQ engine runs faster than the LSQ engine because it runs a reduced number of incremental adjustments toward the goal Configuring the Modified LSQ engine 1 From the Advanced Analysis Edit menu select Profile Settings Click the Optimizer tab From the Engine drop down list select Modified LSQ Profile Settings x Optimizer Monte Carlo Smoke Simulation The Modified LSQ Engine sometimes runs faster than the LSQ Engine because it runs a reduced number of incremental adjustments towards a goal Curve Fit Error Reference Only Uses only reference file data points for error calculation D Delta 1 Max tt of Optimizations 30 Cutback 0 25 Threshold 0 IT One Goal Least Squares C Minimize Cancel Set Defaut Help 282 PSpice Advanced Analysis Users Guide Product Version 10 5 Modified LSQ engine 4 Edit default values in the text boxes
9. See detailed explanations provided on the next few pages 5 Select the One Goal option that you prefer Least Squares or Minimize See Single goal optimization settings on page 286 for details 6 Click OK Modified LSQ Engine Default Options Function Value Delta The relative amount as a percentage of current parameter value 196 the engine moves each parameter from the proceeding value when calculating the derivatives Max of The most attempts the Modified LSQ Engine should make before 20 Optimizations giving up on the solution even if making progress Cutback The minimum fraction by which an internal step is reduced while 0 25 the Modified LSQ Engine searches for a reduction in the goal s target value If the data is noisy consider increasing the Cutback value from its default of 0 25 Threshold The minimum step size the Modified LSQ engine uses to adjust 0 the optimization parameters Delta calculations The optimizer uses gradient based optimization algorithms that use a finite difference method to approximate the gradients gradients are not known analytically To implement finite differencing the Modified LSQ engine 1 Moves each parameter from its current value by an amount Delta Evaluates the function at the new value Subtracts the old function value from the new Divides the result by Delta PSpice Advanced Analysis Users Guide 283 Chapter 9 284 Optimization Engines Product Version 10 5 Note
10. and tools available in Capture Accessing online documentation To access online documentation you must open the Cadence Documentation window 1 Doone of the following a From the Windows Start menu choose OrCAD 10 0 programs folder and then the Online Documentation shortcut b From the Help menu in PSpice choose Manuals 2 Doone of the following a From the Windows Start menu choose Cadence Allegro 15 2 programs folder and then the Online Documentation shortcut b From the Help menu in AMS Simulator choose Manuals The Cadence Documentation window appears 3 Click the PSpice category to show the documents in the category 4 Double click a document title to load that document into your web browser PSpice Advanced Analysis Users Guide 13 Chapter Before you begin Product Version 10 5 14 PSpice Advanced Analysis Users Guide Introduction In this chapter Advanced Analysis overview on page 15 Project setup on page 16 Advanced Analysis files on page 18 Workflow on page 18 Numerical conventions on page 20 Advanced Analysis overview Advanced Analysis is an add on program for PSpice and PSpice A D Use these four Advanced Analysis tools to improve circuit performance reliability and yield B Sensitivity identifies which components have parameters critical to the measurement goals of your circuit design B The four Optimizer engines optimize the parameters of key circuit components to me
11. 3 startvalue 3 a db value relative to 3db 3db below startvalue startvalue 3db 3db above startvalue a value relative to max or max 3 maxrng 3 mm min 3 gt minrng 3 Syntax example The measurement definition is made up of m Ameasurement name m Amarked point expression B Oneor more search commands enclosed within curly braces This example also includes comments about B The measurement definition m What arguments it expects when used B Asample command line for its usage 266 PSpice Advanced Analysis Users Guide Product Version 10 5 For power users Any line beginning with an asterisk is considered a comment line Risetime definition Risetime 1 x2 x1 Desc Find the difference between the X values Desc where the trace first crosses 10 and then Desc 90 of its maximum value with a positive Desc slope Desc i e Find the risetime of a step response Desc curve with no overshoot If the signal has Desc overshoot use GenRise Argl Name of trace to search Usage Risetime trace name 1 Search forward level 10 p 1 Search forward level 90 p 2 The name of the measurement is Risetime Risetime will take 1 argument a trace name as seen from the comments The first search function searches forward positive x direction for the point on the trace where the waveform crosses t
12. Arg1 Description of an argument used in the measurement definition These comment lines will be used in dialog boxes such as the Arguments for Measurement Evaluation box dit Measurement EE Max XRange 1l begin x end x y1 HDesctt Find the maximum value of the trace within the specified range Arguments for Measurement Evaluatio Measurement Expression Max XR angel s Measurement Max_ gt Range has 3 argur amp Kill them in now HArg1t Name of trace to search HArg2t X range begin value HArg3t X range end value 1 search forward begin x end x max Name of trace to search X range begin value X range end value Marked Point Expressions syntax A marked point expression calculates a single value which is the value of the measurement based on the X and Y coordinates of one or more marked points on a curve The marked points are found by the search command All the arithmetic operators and all the functions that apply to a single point for example ABS SGN SIN SQRT can be used in marked point expressions The result of the expression is one number a real value PSpice Advanced Analysis Users Guide 259 Chapter 8 Measurement Expressions Search command syntax Product Version 10 5 Marked point expressions differ from a regular expression in the following ways Marked point coordinate values for example x1 y3 are used in
13. B NODE VE E DERATE TYPE PNP x I p Tip To get the port names by opening the symbol in Capture 1 Select the part in Capture 2 From the Edit menu choose Part The symbol view of the part displays 4 Double click the pin The Name field in the Pin Properties dialog box displays the port name 336 PSpice Advanced Analysis Users Guide Product Version 10 5 Optional sections in a device property file Optional sections in a device property file Some simulation models have more than one physical device attached to them In such cases though the simulation model for physical devices is the same the device specific information stored in the device property file is different For example each of the physical device can have different smoke data The device property files of the models that have more than one physical devices attached to them have an index section The index section has an Implementation statement that lists all the physical devices associated with a model A section of the OPAMP PRP file with the Implementation statement is shown below Model name wee appears in the lib file MAX403 Creator Device property file created by prp generator on Sun May 12 19 51 54 IST 2002 Hierarchical yes Implementation MAX403ESA MAX403EPA MAX403CSA _ _ Device name MAX403CP as appears in the olb file Each of the device listed below
14. Common problems and solutions Solution Smoke analysis peak results don t look right measured values are too small Smoke analysis average or RMS measured results are not what expected selected a custom derating or standard derating file in Smoke but my Derating and Max values didn t change My Smoke result has a yellow flag and a cell is grey Transient analysis may not be long enough to include the expected peaks or may not have sufficient resolution to detect sharp spikes Transient analysis may not be set up correctly Need to click the Run button to recalculate the Smoke results with the new derating factors The limit average RMS or peak is not typically defined for this parameter Grey results show the calculated simulation values however grey results also indicate that comparison with the limit may not be valid PSpice Advanced Analysis Users Guide Check the transient analysis results in PSpice Make sure the analysis includes any expected peaks If necessary edit the simulation profile to change the length of the simulation or to take smaller steps for better resolution Check the transient analysis results in PSpice Make sure the average of voltages and currents over the entire range is the average value you re looking for If you want the measurement average to be based on steady state operation make sure the analysis runs long enough and that you only save data for
15. There is a trade off If Delta is too small the difference in function values is unreliable due to numerical inaccuracies However if Delta is too large the result is a poor approximation to the true gradient Editing Delta Enter a value in the Delta text box that defines a fraction of the parameter total range Example If a parameter has a current value of 1075 and Delta is set to 1 the default then the Modified LSQ Engine moves the parameter by 10719 The 196 default accuracy works well in most simulations If the accuracy of your simulation is very different from typical perhaps because of the use of a non default value for either RELTOL or the time step ceiling for a Transient analysis then change the value of Delta as follows Q If simulation accuracy is better smaller adjustments are needed decrease Delta by an appropriate amount Q If simulation accuracy is worse larger adjustments are needed increase Delta by an appropriate amount Note The optimum value of Delta varies as the square root of the relative accuracy of the simulation For example if your simulation is 100 times more accurate than typical you should reduce Delta by a factor of 10 Threshold calculations The Threshold option defines the minimum step size the Modified LSQ Engine uses to adjust the optimization parameters The optimizer assumes that the values measured for the specifications change continuously as the parameters a
16. This implies that the rise time of the pulse will ve varied from 5 nano seconds to 12 nano seconds 6 To add resistor R3 as the next sweep parameter click the sweep type grid corresponding to the component named R3 From the drop down list select Discrete 8 Tospecify the values of resitor R3 click corresponding Sweep Values grid 9 To specify a discrete value for resistor R3 click the New button and enter 5 10 Similarly specify other values as 15 and 20 11 Click OK to close the Sweep Settings dialog box 12 Finally to add capacitor C1 as a sweep parameter and vary the capacitance value click the sweep type grid corresponding to capacitor C1 and select Linear from the drop down list 13 Click the Sweep Values grid 14 Inthe Sweep Settings dialog box specify theStart Value as 1n End value as 1n and number of points as 10 and click OK Sweep Settings E xj Sweep Type Start Value emo End Value e 0 Step Value emo Total number of steps 23 Cancel PSpice Advanced Analysis Users Guide 229 Chapter 7 Parametric Plotter Product Version 10 5 This implies that the sweep analysis will be performed for 10 values of capacitance between 1 nano farads to 1 nano farads 15 Inthe Select Sweep Parameters dialog box click OK to save your changes Select Sweep Parameters jj Sweep Values Linear Start 1 0 End 33 Step 1 1 VALUE MTYPE CGSO Discrete Values 1 41e 010
17. Troubleshooting feature overview 1 ketenes 293 cl PM sara ees Rae ea aE ees ae QT 293 MVOFKTIOW eoe esse gene petto eae en ew O ida hectare dee knew a hen See gto vate E inthe anaes 294 Procedu fe Siert ienke EAEIiGuMiE ett MEE ioe paw Saag ee dt Aged etru te ee eae Bee aaa 295 Blin OG NR ERR RR TOU ELT dee te pase ase cee agen ee bad bn PP 296 Strategy Stat oho edid a bes ine LESE doe Bute db pi EE Moe is Er hed 296 Setting up the example 223 d Ru OE OEC LAGU edad EER RED EE 296 Using the troubleshooting function 2 0 eee 300 Analyzing the tace dala x5 o2 o3 erae EE f orte ERA E E ER EP RP 303 Resolving the optimization 25x ex ue RARUS OUR SU eee ea UA QUA ek eS 305 Common problems and solutions vss gamer RHET RERUM VOR nur edes Bates 308 A Property Elles enero eut bae xol de dicesdre a eb aes 321 Template property file 1 2 dose obse hee e Ue Se en eot mp ete ted 323 The model info section lllee s 325 The model params section x12 3 4A hee yee eee eet ep RES 326 The smoke Section ee ee eee ae 328 zie device property llle urs Ss eric a Roh dae mass ADR Rea a GR EE Apad 333 The device info section llllelle s 334 Optional sections in a device property file sllllssslssse 337 AOS SAY Sore ost tti eat ene S SRL MM EN A 339 lae ER re tetra Set ates eet eet at Are eee ancl 349 July 2005 8 Product Version 10 5 Before you begin Wel
18. information For example You may want to tighten tolerances on component parameters that are highly sensitive or loosen tolerances on component parameters that are less sensitive 1 Right click on the components critical parameter in the Sensitivity Parameters table and select Find in Design from the pop up menu 2 Change the parameter value in the schematic editor 3 Rerun the simulation and check results 4 Rerun Sensitivity During Sensitivity analysis by default Advanced Analysis varies parameter values by 4096 of the tolerance range You can modify the default value and specify the percentage by which the parameter values should be varied within the tolerance range PSpice Advanced Analysis Users Guide 51 Chapter 3 Sensitivity Product Version 10 5 To specify the percentage variation 1 4 From the Edit drop down menu in Advanced Analysis choose Profile Settings In the Profile Settings dialog box select the Sensitivity tab In the Sensitivity Variation text box specify the percentage by which you want the parameter values to be varied Click OK to save the modifications If you now run the Sensitivity analysis the value specified by you would be used for calculating the absolute and relative sensitivity Sending parameters to Optimizer Printing results 52 1 2 Select the critical parameters in Sensitivity Right click and select Send to Optimizer from the pop up menu Select Opt
19. utei eut CES ERE XE VeL tcd ERES ER SS 10 Related docutmentallOD 1 2 o ded terit e e ne cena E rer oae B hale bed ce odere e boe et 11 Accessing online documentation teens 13 1 IntFOQ UC LIOD cues sevice cw er RE OC Pb ce RD cce A 15 MTSE CHIDIGE Lure anrai eea Robur d jet cafus 08 Ate OE Sat Puoi pania d Oe ee 15 Advanced Analysis overview 2 000 eee 15 PrOJeGESelliD 5o deuda aera uia teu eq oru ha aoe en WON Vid aa a oed hag a esci Pad 16 Validating The inital DFOIGCE 2430 var tacta ata gta eE qup darned wear die Eo aa 17 Advanced Analysis files a oats wid tel 0 Jain Fe e os ce ritu gren pur fe 20 Suec raa De Jai ded D eno dtu Sere 18 WOrKHOW sdi thea ERE eU Fan Rede bat b torret Ae s 18 Numerical conventions llle rrr 20 2 REE TEE ot att erre aee ns teatri Leere ree ea i a 23 ride chapter Void iocus bach E toS CE RES ANE opa hee dealt eu Sca Elan dee d s E P dett 23 OVERVIEW cece EE EEE S A EE ESTE EEE E E E T ET 23 Parameterized components 359 pasate a dare eaa 24 Location of Advanced Analysis libraries ee 27 Using Advanced Analysis libraries 5 25 05 t ta aids mE eS haw yy beat eee ae kanes 27 Using the online Advanced Analysis library list 0 ce eee eee 28 Using the library TOOL TID 253 2 2 8 2 Pe ee oko kore aod dos rie ede be Ree 29 Using Parameterized Part IGOR ux ib doe x Ehe CXTRA SM REDE RUN RUE 30 Preparing your design for Advanced Analysis
20. 0 3 0 35 0 4 0 45 0 5 0 55 0 6 0 650 707508085090 95 1 E statistics I Raw heas Statistical Information On Off Profile Measurement Cursor Min Cursor Max Yield Mean Std Dev 3 Sigma 6 Sigma Median Click here to import a measurement created within PSpice L Monte Carlo For Help press F1 ex m Importing measurements from PSpice 182 1 Inthe Statistical Information table click on the row containing the text Click here to import a measurement created within PSpice PSpice Advanced Analysis Users Guide Product Version 10 5 Example The Import Measurement s dialog box appears Import Measurement s 2 Select the four measurements m a a a Max DB V Load Bandwidth V Load 3 Min 10 Log10 V inoise V inoise 8 28e 19 Max V onoise PSpice Advanced Analysis Users Guide 193 Chapter 6 Monte Carlo Product Version 10 5 3 Click OK Hover your mouse over a Click the cell boundary line red or yellow message flag and drag the double headed to read error message arrow to widen cell and view all content lat ies 7 Raw meas On Off Profile ret v rt eme minci O logr UCv inoise v inoiseyiS 28e 13 i vL rt_amp maxtv onoise y Click hara ta imr Click to clear the check mark Measurements and exclude the measurement imported from PSpice from the next analysis 194 PSpice Advanced Analysis Users Gui
21. 0e0 to 20 0e5 Resistor Resistor 5 10 0e 1 to 24 9e5 Resistor Resistor 10 10 0e 1 to 27e5 Resistor Resistor RLO7 51 to 150000 Capacitor Capacitor 1 0e 12 to 1 0 Inductor Inductor 3 9e 6 to 1 8e 2 PSpice Advanced Analysis Users Guide 131 Chapter 4 Optimizer Product Version 10 5 Adding User Defined Discrete Table You can create your own discrete value table for components and variables that you want the Discrete Engine to read in your project directory where you run the Advanced Analysis Optimizer Tasks to be completed for setting up a discrete value table for a user defined variable are m Creating a new discrete value table m Associating the table with the discrete engine m Using the table Creating a new discrete value table 1 Create a file called xyz table 2 Enterthe table as shown START ii 1 2 1 4 fill in other values Associating the table with the discrete engine After creating the table the next step is to add the new discrete table to Advanced Analysis You can create custom derate files at any location and then associate these with the Advanced Analysis discrete engine using the Advanced Analysis Optimizer Settings dialog box 1 From the Advanced Analysis Edit menu select Profile Settings 2 Click the Optimizer tab 3 Select Discrete from the Engine drop down list 132 PSpice Advanced Analysis Users Guide Product Version 10 5 For Power Users 4 Click
22. 183 custom derating selecting the option 153 F 340 D data sorting 47 viewing 48 Delta option 283 derate type 329 derating factor 331 340 derivatives 79 calculating 283 finite differencing 283 design variables table 33 device 340 device property files 18 dialog box Arguments for Measurement Evaluation 243 Display Measurement Evaluation 246 Measurements 243 Traces for Measurement Arguments 244 Discrete engine 290 341 Product Version 10 5 PSpice Advanced Analysis Users Guide discrete sweep 213 discrete value tables 1 discrete values table 341 DIST 25 distribution function 340 flat 341 Gaussian 341 normal 341 skewed 345 uniform 341 distribution parameter DIST 25 E engine Discrete 105 135 290 LSQ 135 269 Modified LSQ 135 282 Random 287 error graph 341 evaluation 77 See Also goal function Probe See Also PSpice Optimizer expression See Also trace function Probe exponential numbers numerical conventions 20 expression 78 F file extensions Find in fees 63 106 flat distribution function 341 G Gaussian distribution function 341 global minimum 270 342 goal 74 75 342 See Also specification goal function Probe 77 discontinuities 78 goal functions 241 July 2005 goals defining for optimization 81 graphs cumulative distribution function 182 cursors 183 monte carlo CDF graph 201 monte carlo PDF graph 181 198 344 optimizer Error Graph 99 102 118 probabilit
23. 257 T technical note creating a custom derating file 143 Temperature Parameters Only 14 test node mapping 328 335 tightening LSQ engine options TOL ON OFF 45 TOLERANCE 35 tolerance as percent or absolute values 25 NEGTOL 25 POSTOL 25 relative convergence 280 X Convergence 280 tolerance parameters TOLERANCE 35 trace parametric plotter 220 trace function Probe 77 troubleshooting table of common problems 308 using the troubleshooting too S N Co rs 293 July 2005 U uniform distribution function 341 units 20 V validating the initial project 17 VALUE 32 variables component 33 view plot 225 W weight workflow monte carlo 176 optimizer 80 overall 18 sensitivity 44 smoke 139 worst case maximum worst case minimum Y yield 346 yield analysis see Monte Carlo 346 346 346 Product Version 10 5
24. 343 measurement definition 241 output variable 241 output variables 241 value in PSpice 242 viewing inPSpice 242 measurement expressions composing 241 creating 241 parametric plotter 219 PSpice Simulation Results view 241 setup 240 July 2005 Simulation Results view 241 measurement expressions included in PSpice list 247 measurement results PSpice view menu 242 measurements overview 239 minimization 286 constrained 73 minimization algorithm 286 Minimize option 287 model 343 Modified LSQ engine 342 Modified LSQ engine options 283 monte carlo adding ameasurement 186 allowable PSpice simulations 17 analysis runs 179 CDF graph 182 controlling measurement specifications 186 cursors 183 distribution parameters 25 editing a measurement 186 editing a measurement spec min or max value 186 example 189 excluding a measurement from analysis 186 overview 173 pausing analysis 185 pdf graph 181 printing raw measurement data 187 procedure 177 raw measurements table 184 restricting calculation range 183 resuming analysis 185 statistical information table 180 stopping analysis 185 strategy 174 workflow 176 monte carlo results 3sigma 181 6 sigma 181 cursor max 181 cursor min 181 mean 181 median 181 standard deviation 181 yield 181 monte carlo setup options 351 Product Version 10 5 PSpice Advanced Analysis Users Guide number of bins 179 Number of runs 181 number of runs 178 random seed value 17 s
25. Advanced Analysis Users Guide Product Version 10 5 For power users 5 Specify the property value as myderatetype3 which is same as the derate type specified by you in the sample drt file and click OK wi sample drt Notepad File Edit Format Help C FILE_TYPE Derate File C myderatetypel C category RES PDM 55 C Tmax 0 40000000000000 TB 0 70000000000000 C myderatetype2 C category RES C TmMax Q 70000000000000 TB 0 90000000000000 2 C myderatetype3 Category Cv 0 30000000000000 cap Value assigned to the DERATE_TYPE is same as the derate type specified in the drt file Froperty Editor Designator DIST 6 Regenerate the PSpice netlist From the PSpice drop down menu select Create Netlist 7 Runthe smoke analysis From the PSpice drop down menu select Advanced Analysis and then choose Smoke PSpice Advanced Analysis Users Guide 169 Chapter 5 Smoke Product Version 10 5 8 In Advanced Analysis ensure that the sample drt file is loaded and active Then run the smoke analysis Smoke tran sim Derating File sample drt omponent Parameter Type Rated Value Derating Note To know more about loading a customized derate file to your design see Adding the custom derating file to your design on page 165 170 PSpice Advanced Analysis Users Guide Product Version 10 5 Supported Device Categories For power users
26. Analysis Users Guide Product Version 10 5 Example A pop up menu appears Import Spies wpumzer Mara E Troubleshoot in PSpice 2 From the pop up menu select Troubleshoot in PSpice PSpice Advanced Analysis Users Guide 301 Chapter 10 Troubleshooting Product Version 10 5 PSpice opens and the measurement specification data displays in the window AAA 2 5 ESRCSISESN C A pay amp Q m ree B ez hose er Dot AE 20 The first trace shows the data o TEPPE m TEEPEE Oet nnn nena nnn from the run with ig mfomaion tg REESE en Lc DOO the original Properties SCANS A ee To identify a trace right B The second trace NEN l click on it and select values sor i Jill shows the data from m Information H the last run 1 6MHZ 188HHz 1 6GHz db U Load Frequenc Measurement Results Evaluate Measurement Bandwidth v Load 3 15060380meg sEvaluation Failed Click here to evaluate a new measurement amp rf ampt SCH Simulation complete 3 E F gt S USE Analysis A Watch A Devices Information Freq 1 000E 09 100 NEENEEEEEEE HI Z A message appears db V Load a bo ut th e trace d ata This trace came from one simulation run from the data file C Cadence PSD_14 11PSpicelTutoriall TroubleShooting CapturelMrfamp trf ampt s
27. B A circuit schematic and working PSpice simulation PSpice Advanced Analysis Users Guide 139 Chapter 5 Smoke Running Smoke Starting a run 140 Product Version 10 5 Measurements set up in PSpice Performance goals for evaluating measurements Performance goals Smoke analysis also requires Any components included in a Smoke analysis must have smoke parameters specified For more information see Chapter 2 Libraries Time Domain transient analysis as a simulation Smoke does not work on other types of analyses such as DC Sweep or AC Sweep Noise analyses From your schematic editor open your circuit Run a PSpice simulation Check your key waveforms in PSpice and make sure they are what you expect Note For information on circuit layout and simulation setup see your schematic editor and PSpice user guides See Smoke parameters on page 154 In your schematic editor from the PSpice menu select Advanced Analysis Smoke Smoke automatically runs on the active transient profile Smoke calculates safe operating limits using component parameter maximum operating conditions and derating factors The output window displays status messages PSpice Advanced Analysis Users Guide Product Version 10 5 Viewing Smoke results Red bar exceeds the limit Yellow bar is within 90 of the limit Green bar is anywhere below 90 of the limit IM Smoke procedure To see Average RMS and Peak values right
28. Error Reference Only Uses only reference file data points for error calculation Cancel Set Defaut Help To view and change the default options 1 From the Advanced Analysis Edit menu select Profile Settings 2 Click the Optimizer tab and select Random from the Engine drop down list 3 Editthe default value in the text box 288 PSpice Advanced Analysis Users Guide Product Version 10 5 Random engine 4 Click OK Random Engine Options Default Value Steps per Range 10 Max Number of Runs 10 Replay Best N Runs at End 0 Random Number 0 Generator Seed Steps per Range Specifies the number of steps into which each parameter s range of values should be divided For example if this option is set to 7 and you have the following parameters Parameter Min Max A 1 4 B 10 16 The possible parameter values would be Parameter A 1 1 5 2 2 5 3 3 5 4 Parameter B 10 11 12 13 14 15 16 Max Number of Runs Specifies the maximum number of random trial runs that the engine will run The engine will run either the total number of all grid points or the number specified in this option whichever is less Note With 10 parameters the number of grid points in the design exploration NumSteps Params would be 819 1 073 741 824 PSpice Advanced Analysis Users Guide 289 Chapter 9 Optimization Engines Discrete engine 290 Product Version 10 5 For example if Max Numbe
29. Error Graph with history 1 cleared s 05 155 M N Ri Himbeer Ee eee 7 Make sure the Modified LSQ engine is selected and Click on the top toolbar to start the optimization E File Edit View Run Analysis Window Help ca S amp db B Ortiz Modified La p i Click to start optimization PSpice Advanced Analysis Users Guide 299 Chapter 10 Troubleshooting Product Version 10 5 The optimization starts and makes four run attempts Specifications Hext Run v z E ri amet schenati vw E ricametcschemati ww Bel EZ rf ampt schematic Min t O Logt OC v inoise vino v TED NS ricomet schemetic Maxcvconoisey EN A red flag marks the specification with the problem measurement 7 Measureme Max DB Load Bandwicdth v Load 3 ptimizer ES Starting Optimizer P d Processing analysis specifications Loading Modified L5Q engine Optimization sensitivity run 0 Optimization run 1 Optimization run 2 The log file reports a specification Optimization run 3 error Optimization run 4 lll Specification error Level search Failed Spec Bandwidth V Load 3 Analysis stopped The Optimizer failed to find a solution Let s troubleshoot the problem measurement in PSpice Using the troubleshooting function 300 1 Right click in the specification row marked by the red flag second row Bandwidth V Load 3 PSpice Advanced
30. Find in Design The schematic editor appears with the components highlighted Editing a measurement within Advanced Analysis At some point you may want edit a measurement You can edit from the Specifications table but any changes you make will not appear in measurements in the other Advanced Analysis tools or in PSpice 1 Click on the measurement you want to edit A tiny box containing dots appears On Off Profile Measurement kal e 2 r amp sche max ab viload L v Lll E rt_amp sche bandwidth v load 3 Ur e did EZ rf amp sche mina 0 log1 O v inoise v inoise 8 28e 19 sll e A E ri amp sche max vfoncise al Click here to import a meAsure Click to edit 2 Click zl PSpice Advanced Analysis Users Guide 123 Chapter 4 Optimizer Printing results Saving results 124 Product Version 10 5 The Edit Measurement dialog box appears Profile rf amp schematic1 ac sim r Simulation Output Variables r Functions or Macros Measurements i Bandwidth 1 db level Bandwidth Bandpass 3dB 1 Bandwidth Bandpass 3dB XRar a IV Voltages IV Currents JV Power CenterFrequency 1 db level CenterFrequency XR ange db ConversionGain 1 2 M ale ConversionGain_ Range 1 2 bec Y I C5 B xi Full List Measurement Cancel Hep 3 Make your edits Its a good idea to edit and run your measurement in PSpice and check its per
31. If appropriate change the range of any parameter that is near its limit to allow the parameter to exceed the limit If the limit cannot be changed you may want to disable that parameter because it is not useful for optimization and will make the analysis take longer PSpice Advanced Analysis Users Guide 313 Chapter 10 Troubleshooting Results are not what you expected Return to top of table Problem Results are not Possible cause what you expected Product Version 10 5 Solution set up my circuit and ran Your components may not Smoke but I m not getting have smoke parameters the results expected specified Check the online Advanced Analysis Library List and PSpice library list for a complete list of components supplied with smoke parameters Replace your existing components with those containing smoke parameters Or For R L and C components add the design variables table default variables to your schematic This table contains default smoke parameters and values See the Libraries chapter of this manual for instructions on how to add this table to your schematic Or Add smoke parameters to your component models using the instructions provided in our technical note Creating Models with Smoke Parameters which is available on www orcadpcb com 314 PSpice Advanced Analysis Users Guide Product Version 10 5 Problem Results are not what you expected Possible cause
32. PSpice Advanced Analysis Users Guide Product Version 10 5 Max_XRange Min M tink Range PSpice Advanced Analysis Users Guide Example Maximum value of the waveform within the specified range of X Minimum value of the waveform Mintsutmevalue of the waveform within the specified range of X 251 Chapter 8 Measurement Expressions SettlingTime SettlingTime XRange Product Version 10 5 Time from lt begin_x gt to the time it takes a step response to settle within a specified band Time from lt begin x gt to the time it takes a Definition Era egRo nse to settle within a specified and and within a specified range 252 PSpice Advanced Analysis Users Guide Product Version 10 5 For power users Definition Finds the YatX Value of the waveform at the given X_value YatX_PercentXRange ZeroCross ZeroCross XRange Value of the waveform at the given percentage of the X axis range X value where the Y value first crosses zero X value where the Y value first crosses zero at the specified range For power users Creating custom measurement definitions Strategy Measurement definitions establish rules to locate interesting points and compute values for a waveform In order to do this a measurement definition needs m A measurement definition name So it will come when it s called m Amarked point expression These are the calculations that compute the final point on the wav
33. PSpice Advanced Analysis Users Guide 105 Chapter 4 Optimizer Product Version 10 5 Finding components in your schematic editor Saving results Examining a Run in PSpice 106 You can use the Find in Design feature to return to your schematic editor and locate the components you would like to change 1 Inthe Parameters table highlight the components you want to change 2 With the components selected right click the mouse button A pop up menu appears 3 Select Find in Design The schematic editor appears with the components highlighted Click Il Or From the File menu select Save The final results will be saved in the Advanced Analysis profile aap During the optimization process one or more optimizer runs can fail To investigate optimization failures Select Analysis Optimizer Troubleshoot in PSpice The simulation profile associated with the selected measurement opens in PSpice PSpice then automatically opens the waveform viewer and shows a comparison of the last Optimizer simulation to a nominal PSpice simulation PSpice lists results for both runs in the Measurement spreadsheet for easy comparison PSpice Advanced Analysis Users Guide Product Version 10 5 Example Example This section covers two design examples The first example domesticates optimizing a design using measurement specifications The second design example covers optimizing a design using curve fit specifications
34. Positive 264 PSpice Advanced Analysis Users Guide Product Version 10 5 For power users PEak Finds the nearest peak At least consecutive_points points on each side of the peak must have Y values less than the peak Y value TRough Finds nearest negative peak At least consecutive_points points on each side of the trough must have Y values greater than the trough Y value MAx Finds the greatest Y value for all points in the specified X range If more than one maximum exists same Y values then the nearest one is found MAx is not affected by direction amp consecutive points or repeat Min Finds the minimum Y value for all points in the specified X range Min is not affected by direction consecutive_points or repeat POint Finds the next data point in the given direction XValue value Finds the first point on the curve that has the specified X axis value The value is a floating point value or percent of full range XValue is not affected by direction consecutive_points range x range y or repeat PSpice Advanced Analysis Users Guide 265 Chapter 8 Measurement Expressions Product Version 10 5 value can take any of the following forms Value form Example a floating number 1e5 100n 1 a percentage of full range 50 a marked point x1 y1 or an expression of x1 x2 2 marked points a value relative to 3 gt startvalue 3 startvalue
35. See Chapter 2 Libraries for information about component tolerances From your schematic editor open your circuit Run a PSpice simulation Note Advanced Analysis Monte Carlo does not use PSpice Monte Carlo settings Note You can run Advanced Analysis Monte Carlo on more than one simulation profile at once However if you have a multi run analysis set up in PSpice for example a parametric sweep or a temperature sweep Advanced Analysis Monte Carlo will reduce the simulation profile to one run before starting the Advanced Analysis Monte Carlo calculations For temperature sweeps the first temperature value in the list will be used for the Advanced Analysis Monte Carlo calculations Check your key waveforms in PSpice and make sure they are what you expect Test your measurements and make sure they have the results you expect For information on circuit layout and simulation setup see your schematic editor and PSpice user guides PSpice Advanced Analysis Users Guide 177 Chapter 6 Monte Carlo Product Version 10 5 Note For information on setting up measurements see Procedure for creating measurement expressions on page 240 Setting up Monte Carlo in Advanced Analysis Opening Monte Carlo From the PSpice menu in your schematic editor select Advanced Analysis Monte Carlo The Advanced Analysis Monte Carlo tool opens Importing measurements from PSpice 1 Inthe Statistical Information table click
36. Settings Simulation Q From the Monte Carlo field select Save None The simulation data will be overwritten by each new run Only the last run s data will be saved Importing measurements Ww Find the most sensitive measurements in Sensitivity and perform Monte Carlo analysis on those measurements only Limiting Monte Carlo to only important measurements saves run time PSpice Advanced Analysis Users Guide 175 Chapter 6 Monte Carlo Product Version 10 5 Workflow Schematic editor PSpice Advanced Analysis Set up or edit circuit Simulate the circuit Import Measurements Set Monte Carla Create measurements options Check waveforms and Run Monte Carla measurement results Change components or edit tolerance and Does design distribution parameter meet Values requirements Print the results These processes are explained in your schematic editor and save the results PSpice user guides 176 PSpice Advanced Analysis Users Guide Product Version 10 5 Monte Carlo procedure Monte Carlo procedure Setting up the circuit in the schematic editor Starting out Have a working circuit in Capture Circuit simulations and measurements should already be defined The simulations can be Time Domain transient DC Sweep and AC Sweep Noise analyses The circuit components you want to include in the data need to be Advanced Analysis ready with the tolerances of the circuit components specified
37. Value form Example a floating number 1e5 100n 1 a percentage of full range 50 PSpice Advanced Analysis Users Guide 263 Chapter 8 Measurement Expressions Product Version 10 5 Value form Example a marked point x1 y1 or an expression of x1 x2 2 marked points a value relative to 3 gt Startvalue 3 startvalue 3 2 startvalue 3 a db value relative to 3db 3db below startvalue startvalue 3db 3db above startvalue a value relative to max or max 3 gt maxrng 3 mn min 3 2 minrng 3 a db value relative to max max 3db gt 3db below maxrng or min min 3db 3db above minrng decimal point A decimal point represents the Y value of the last point found using a search on the current trace expression of the goal function If this is the first search command then it represents the Y value of the startpoint of the search SLope posneg Finds the next maximum slope positive or negative as specified in the specified direction posneg refers to the slope going Positive P Negative N or Both B If more than the next consecutive_points points have zero or opposite slope the Slope function does not look any further for the maximum slope Positive slope means increasing Y value for increasing indices of the X expression The point found is an artificial point halfway between the two data points defining the maximum slope The default posneg is
38. X and Y ranges are limited 5m 1 10 90 both X and Y ranges are limited 100 1 3 full X range limited Y range 51 3 full X range limited Y range 0 C1 30n X range limited only on upper end for repeat Specifies which occurrence of conditions to find If repeat is greater than the number of found instances of lt condition gt then the last condition found is used Example The argument 2 LEvel would find the second level crossing condition Must be exactly one of the following a LEvel value posneg PSpice Advanced Analysis Users Guide Product Version 10 5 For power users SLope posneg PEak TRough MAx Min POint D oO 0 D D D UD XValue value Each condition requires just the first 2 characters of the word For example you can shorten LEvel to LE Ifa condition isnot found then either the cursor is not moved or the goal function is not evaluated LEvel vahlue posneg posneg Finds the next Y value crossing at the specified level This can be between real data points in which case an interpolated artificial point is created At least consecutive points 1 points following the level crossing point must be on the same side of the level crossing for the first point to count as the level crossing posneg can be Positive P Negative P or Both B The default is Both value can take any of the following forms
39. and then displayed in the Max column For example if the calculated value of Max is 57 06 the value displayed in the Max column will be 58 Right click on the table and select Temperature Parameters Only from the pop up menu Only maximum resistor or capacitor temperature TB and maximum junction temperature TJ parameters are displayed When reviewing these results only average and peak values are meaningful PSpice Advanced Analysis Users Guide 149 Chapter 5 Smoke Product Version 10 5 In this example none of the parameters are stressed as indicated by the green bars Right click to select average Shows the derating factor Shows the parameti RMS and peak values percentage measurement for example voltage Right click to select The calculated SOL is the max e pee temperature only derating temperature parameters SOL MOC x derating rf amp SCHEMATICI PSpice Advanced Analysis smoke Aol x Max is the actual operating value SOL x 100 BH File Edit Wew Run Analysis Windo Pu le s 8 A Lel CO efratic1 tran sim num Ie Re GU 9 Ie Srp ke rf amp schernatic1 tran sim Ho Derating Component Pai eter ype Derating Max Derating Measured Value Green bars show values within the safe operating limits Starting Smoke Analysis ____ Status messages Smoke Analysis succeeded Smoke Analysis Finished
40. antiq ens EU EC e 146 Gonllgurlnd Smoke 14e e Sei ea Mk ene bn lad An C dec fea Dear Meo haters ete e 151 For power USEIS 3 323 oto i sir LE Rud br RS ee eS II RULES tee ek er Ps 154 Smoke parameters 11 2206 9 9 05 0 eiaha Doe a da ea a B9 e boe ub aS e nid dus eO br ed 154 Adding Custom Derate file 22 59 rere SR IP ER EARS RR SU PE RE 160 Supported Device Categories nnn 171 6 Monte Carlo a na anaana RR 173 da RT Relur ieli RR REEL QE 173 Monte Carlo Overview 24 44a eb E exe ER EAR eae sow Rei epa d we 173 July 2005 5 Product Version 10 5 PSpice Advanced Analysis Users Guide Monte Cano strategy 15 estore deta dated ee aes SU eon ette etek See edd 174 Platea 4x oro pua un gai ate V a IE easel ie BN aN OF Sai dunt 174 WVORKTIOW Ln andas cate por eu rte ka Fab usado eru ghhq ug E whe alk whe OP eder is 176 Monte Carlo procedure 2 cs ose ESAE Ae SA es cee ee ROCA RN 177 Setting up the circuit in the schematic editor lllsss 177 Setting up Monte Carlo in Advanced Analysis 000 cece eens 178 Running Monte Carlo 4329s enps Sep e Y ere toads taser ce A RS E IER UN QUU RUE 179 Reviewing Monte Carlo data 35 tescuects ak E eh beeen n eu e ex dr dE RE ES 180 Controlling Morte allo opaco t ctr etate ee aru oe La RC ta QUA ERE 184 Printing POSES T xoa ood duod eda OS dar ck ob E dtes D didi Fu aru ues STi pci 186 Savitig Tesis vct matu s
41. are B PSpice simulation profiles sim m Advanced Analysis profiles aap Advanced users may also use these files m Device property files prp For more information see Appendix A Property Files B Custom derating files for Smoke drt For more information see the technical note titled Creating Custom Derating Files for Advanced Analysis Smoke on www orcadpcb com W Discrete value tables for Optimizer table For more information see What are Discrete Tables on page 131 Workflow There are many ways to use Advanced Analysis This workflow shows one way to use all four features 18 PSpice Advanced Analysis Users Guide Product Version 10 5 Workflow Schematic editor PSpice Advanced Analysis Set up or edit the Import measurements Create Run Sensitivity measurements Check waveforms and Export parameters to measurement results Optimizer circuit Run Optimizer Change components Does or edit parameter meet iss Srt values requirements Run Monte Carlo to check yield Is yield good enough Run Smoke Are any components smoking Change derating factors These processes are rei explained in your Update the schematic schematic editor and with new values PSpice user guides Save the results PSpice Advanced Analysis Users Guide 19 Chapter 1 Introduction Numerical conventions Product Version 10 5 PSpice ignores units such as Hz dB Far
42. b From the Optimizer drop down list select Save All Runs if you want the simulation data to be stored and select Save None if you do not want the simulation data to be stored 7 Select an engine and start the Advanced Analysis Optimizer 98 PSpice Advanced Analysis Users Guide Product Version 10 5 Running Optimizer Starting a run Displaying run data Clearing the Error Graph history Optimizer procedure overview Click I on the top toolbar The optimization analysis begins The messages in the output window tell you the status of the analysis A nominal run is made with the original component parameter values As the optimization proceeds the Error Graph shows a plot with an error trace for each measurement Data in the Parameters and Specifications tables is updated Place your cursor anywhere in the Error Graph to navigate the historical run data The Parameters and Specifications tables display the corresponding data calculated during that run The optimization engine used for each run is displayed in the Optimization Engine drop down list box Though the engine name is displayed the list box is disabled indicating that you can only view the engine used for the optimizer run selected in the Error Graph Note The Advanced Analysis Optimizer saves only the engine name associated with the simulation run Engine settings are not saved Selecting the Clear error graph history retains the value of paramete
43. click and from the pop up menu select the values you want to review Check the bar graph Q Red bars show values that exceed safe operating limits Q Yellow bars show values getting close to the safe operating limits between 90 and 100 percent of the safe operating limits Q Green bars show values within safe operating limits less than 90 percent of the safe operating limits Q Grey bars indicate the limit is not available for the parameter Safe operating limit To decipher the acronym for a parameter right click and from the pop up menu select Parameter Descriptions To view temperature parameters only right click and from the pop up menu select Temperature Only Parameters Only average and peak values are useful when viewing temperature parameters To change the sort order of a column click on the column header To locate a problem component in your schematic right click on a component parameter and select Find in Design from the pop up menu PSpice Advanced Analysis Users Guide 141 Chapter 5 Smoke Printing results Configuring Smoke Product Version 10 5 This returns you to the schematic editor with the component selected Click amp Or From the File menu select Print Changing components or parameters Smoke results are read only To modify the circuit 1 Make your changes in your schematic editor 2 Rerun the PSpice simulation Follow the steps for Setting up the c
44. could be POWER 0 25 W To analyze a circuit component with an Advanced Analysis tool make sure the component contains the following parameters This Advanced Uses these component Analysis tool parameters Sensitivity Tolerance parameters Optimizer Optimizable parameters Smoke Smoke parameters PSpice Advanced Analysis Users Guide Product Version 10 5 Overview This Advanced Uses these component Analysis tool parameters Monte Carlo Tolerance parameters Distribution parameters default parameter value is Flat Uniform Tolerance parameters Tolerance parameters define the positive and negative deviation from a component s nominal value In order to include a circuit component in a Sensitivity or Monte Carlo analysis the component must have tolerances for the parameters specified Use the Advanced Analysis library list to identity components with parameter tolerances In Advanced Analysis tolerance information includes M Positive tolerance For example POSTOL for RLC is the amount a value can vary in the plus direction M Negative tolerance For example NEGTOL for RLC is the amount a value can vary in the negative direction Tolerance values can be entered as percents or absolute numbers Distribution parameters Distribution parameters define types of distribution functions Monte Carlo uses these distribution functions to randomly select tolerance values within a range PSpice Adva
45. displays PSpice Advanced Analysis Users Guide 173 Chapter 6 Monte Carlo strategy Monte Carlo Plan Ahead 174 Setting options Product Version 10 5 Displaying results in a probability distribution function PDF graph Displaying results in a cumulative distribution function CDF graph Calculating statistical data Displaying measurement values for every Monte Carlo run Monte Carlo requires Circuit components that are Advanced Analysis ready See Chapter 2 Libraries A circuit schematic and working PSpice simulation Measurements set up in PSpice See Procedure for creating measurement expressions on page 240 Start with enough runs to provide statistically meaningful results Specify a larger number of runs for a more accurate graph of performance distribution This more closely simulates the effects of mass production Start with a different random seed value if you want different results Set the graph bin number to show the level of detail you want Higher bin numbers show more detail but need more runs to be useful If you are planning an analysis of thousands of runs ona complex circuit you can turn off the simulation data storage option to conserve disk space However at this PSpice Advanced Analysis Users Guide Product Version 10 5 Monte Carlo strategy setting the simulation will run slower To turn off data storage Q From the Advance Analysis menu select Edit Profile
46. distribution function Related to Monte Carlo For a Gaussian Normal distribution function the program has a higher probability of choosing from a narrower range within the allowed tolerance values near the mean PSpice Advanced Analysis Users Guide 341 Glossary global minimum goal L Least Squares Quadratic LSQ engine local minimum LSQ engine Maximum Operating Conditions MOCs Modified Least Squares Quadratic LSQ engine 342 Product Version 10 5 Related to the Optimizer The global minimum is the optimum solution which ideally has zero error But factors such as cost and manufacturability might make the optimum solution another local minimum with an acceptable total error A desirable numerical value in circuit optimization A goal may not be physically achievable but the optimization engine tries to find answers that are as close as possible to the goal A goal is specified by the user according to the user s design specifications One of the most common circuit optimization engines for optimizing to fixed goals Optimizes the design by minimizing the total error Related to the Optimizer Local minimum is the bottom of any valley in the error in the design space See least squares quadratic LSQ engine and Modified LSQ engine Maximum safe operating values for component parameters in a working circuit MOCs are defined by the component manufacturer A circuit optimiz
47. eee ee eee 247 Eor power WS OG o uto suh eru ond re eee anche ate des or der quare orca dt pd EAE a a ES as 253 Creating custom measurement definitions 0 ees 253 Beto example 3558251 527 ieee toe hes LE Sia ae ee Ee es 255 Measurement definition syntax llle 257 SUITS OXAITIDIB sacs Oh mo pd ee SR Sou P On eee oes d p be Dir n 266 9 Optimization Engines sx p EE ease bn 269 AAAS chapter ae eed See sah cele sk eh aa ahead hed co o ag Dog DAT UA aba e CATE BERS 269 LS GHI 2 50 a seo ep weeds BOE de le Soh we he pond Se cipPen Go BO do a RUG did qa onda a Ne Bond 269 Principles of operatio 5 2 aea bac pac Bn rn fot mao Bear M A ne Afer te fed 270 Configuring the LSQ engine 22v Lnsbuc REDRERESND sede e EAD EEDESERBGS 277 Modified LSQ engine 1 9e oes Seka E owe esi ROS Sb RESO Baas dece iode dfe eit 282 Configuring the Modified LSQ engine cee ee 282 Random ngine ix od aa DdnDi nero onthe aon eae wa aD Reet neath ad nem meee es A 287 Configuring the Random Engine oasacvaoe vere Lax x gol a a Pea Gera eA CR cx 288 DISCKEIE ONGOING 732 tue priora Errare NE oe ra yet Round fabri aee Skate Abt eco iUnd 290 Commercially available values 0 000 ee 292 July 2005 T Product Version 10 5 PSpice Advanced Analysis Users Guide 10 TFOUDIESHOOUNG oet intrent e ater e ete 293 Indhis chapter 12 2299 e ie ee sons aee AAE hatte ee tet ad ad ah RE Sas 293
48. evaluated at each sweep See Specifyin measurements on page 218 After you have identified the sweep parameters and specified measurements run the sweep analysis and view the results in the Results tab or the Plot Information tab of the Measurements window Advanced Analysis Parametric Plotter is used to perform the sweep analysis When you run a sweep analysis you evaluate the results of sweeping one or more parameter values on the circuit output During the sweep analysis the parameters values are varied as per the user specifications There are four possible ways in which you can vary the parameter values These are m Discrete Sweep Linear Sweep 8 m Logarithmic octave sweep 8 Logarithmic decade sweep For discrete sweep you need to specify the actual parameter values to be used during the simulation runs The parameter values are used in the order they are specified Example You can specify the values of variable parameters as 10 100 340 and so on PSpice Advanced Analysis Users Guide 213 Chapter 7 Parametric Plotter Linear Sweep Logarithmic octave sweep 214 Product Version 10 5 For Linear sweep specify the Start End and Step values For each run of the parametric plotter the parameter value is increased by the step value In other words the parameter values used during the simulation runs is calculated as Start Value Step Value This cycle continues till the parameter
49. followed in case multiple more than two parameter values need to be varied For example in Figure 7 3 on page 217 for constant values of r7 and r6 the value of r4 will be varied The values of r7 and r6 will not change till r4 has been assigned all possible values within the range specified by the user After r4 completes a cycle the value of r6 will be increased and r4 will again be varied for all possible values Specifying measurements 218 Parametric Plotter is used for evaluating the influence of changing parameter values on an expression and on a trace A measurement can be defined as an expression that PSpice Advanced Analysis Users Guide Product Version 10 5 Specifying measurements evaluates to a single value where a trace is an expression that evaluates to a curve Adding measurement expressions You can either add a measurement expression that was created in PSpice A D or can even create a new measurement in PSpice Advanced Analysis Adding measurements created in PSpice 1 Inthe Measurements tab click the Click here to import a measurement created in PSpice row The Import Measurements dialog box appears This dialog box lists only the measurements that you created in PSpice A D 2 Select the measurement that you want to be evaluated and click OK Selected measurement gets added in the Measurements tab Qpp Tip Only the measurements that are listed in the Measurements Results wi
50. ie not be commercially Error Graph Parameters Hext Run m x 70 2 V o On Off Component Parameter Original Min Max Current available an siel A je VALUE 3 ss500 35700 NJ 20 eika jns VALUE 235 705 702 5752 30 viii 705 238 8924 LE Ea max db v load 5 5000 Constraint bbandwidth v load 3 200000000 min 10 log1 O v inoise 5 Constraint max v onoise 3n Constraint 20 Click here to import a measurement created within PSpice T 225752 238 0824 E ptimizer x Optimization run 4 a m Optimization run 5 Optimization complete For Help press F1 Wu 4 PSpice Advanced Analysis Users Guide 119 Chapter 4 120 Optimizer Product Version 10 5 1 Fromthe top toolbar engine text box select Discrete from the drop down list r Modiiea LSQ gt Modified LSQ L50 Random Discrete A new column named Discrete Table appears in the Parameters table Discrete values tables for RLC components are provided with Advanced Analysis 2 To select a discrete values table click on any RLC component s Discrete Table column You will get a drop down list of commercially available values discrete values tables for that component Parame On Off Component Parameter Discrete Table gt e eee A e je VALUE ne A e js VALUE Resto Es pick Click h 3 istor 1096 sn 2 RLO7 Click here and sele
51. log v noiseY 5 ac sim max v onoise 3n Click here to import a measurement Original i Current xi Loading Discrete engine k 3 E B T 3 B D D D Optimzationrun amp a aaaa oo Emm a RN NN n ao acu 240 For Help press F1 5 Return to your schematic editor and change Q R8 to 3 6 ohms a R 6 to 680 ohms Q R4 to 240 ohms Note You can use Find in Design to locate components in your schematic editor See Finding components in your schematic editor PSpice Advanced Analysis Users Guide 121 Chapter 4 122 Optimizer Product Version 10 5 6 While you are still in your schematic editor rerun the simulation titled AC Check your waveforms and measurements in PSpice and make sure they are what you expect Finding components in your schematic editor You can use Find in Design from Advanced Analysis to return to your schematic editor and locate the components you would like to change 1 Inthe Parameters table highlight the components you want to change IH Upumizer pes moaned Lol Click here to select components hold down shift key to select several 2 With the components selected right click the mouse button A pop up menu appears Import Parameters Find in Design Import Pspice Optimizer Data db Cut Copy e Paste Delete PSpice Advanced Analysis Users Guide Product Version 10 5 Example 3 Leftclick on
52. measurement results fell within design specifications PSpice Advanced Analysis Users Guide Product Version 10 5 Glossary PSpice Advanced Analysis Users Guide 347 Glossary Product Version 10 5 348 PSpice Advanced Analysis Users Guide PSpice Advanced Analysis Users Guide Index Symbols 87 88 lt MIN gt 49 Max 60 Min 60 A absolute sensitivity 339 accuracy and RELTOL 284 and Threshold value 286 accuracy of simulation adjusting Delta value for 284 optimum Delta value variation 284 add plot 223 adding measurement expressions in parametric Plotter 219 plots in parametric Plotter 223 sweep parameters 216 traces in parametric Plotter 220 advanced analysis files 18 algorithm least squares 270 least squares quadratic 278 arctan function mapping parameters with 274 B bar graph style linear view 61 log view 61 bimodal distribution function 339 C CDF graph 182 circuit preparation adding additional parameters 32 July 2005 creating new designs 31 modifying existing designs 35 selecting parameterized components 31 setting parameter values 31 using the design variables table 33 clear history 100 component 340 component parameter 340 configuring the Monte Carlo tool 178 the Optimizer tool 83 the Sensitivity tool 45 the Smoke tool 151 constraint 74 75 340 See Also specification convergence false 280 cross hatched background 102 cumulative distribution function CD cursors
53. on the row containing the text Click here to import a measurement created within PSpice The Import Measurement s dialog box appears 2 Select the measurements you want to include For more information see Importing measurements from PSpice on page 192 in the Example section Setting Monte Carlo options From the Advanced Analysis Edit menu select Profile Settings click the Monte Carlo tab and enter the following Monte Carlo options m Number of runs This is the number of times the selected simulation profiles will be run For each run component parameters with tolerances will be randomly varied Run number one uses nominal component parameter values The maximum number of runs is primarily limited by the amount of available memory B Starting run number 178 PSpice Advanced Analysis Users Guide Product Version 10 5 Monte Carlo procedure The default starting run number is one This is the nominal run If the random seed value is kept constant then you can change the starting run number in order to duplicate a partial Monte Carlo simulation You can use this to isolate specific random results which are of particular interest without having to run an entire Monte Carlo simulation again m Random seed value The random number generator uses this value to produce a sequence of random numbers Change the seed in order to produce a unique random sequence for each Monte Carlo simulation If the seed and device prope
54. overshoot of the zero point and the normalized values tend to bounce back and forth between near minimum and near maximum values This bouncing can occur for several iterations but usually stops as the parameter values move out of this area PSpice Advanced Analysis Users Guide Product Version 10 5 Configuring the LSQ engine LSQ engine In most cases you do not need to change the LSQ default options The engine defaults do the best job in almost all situations In the event that you do need to change a default option use the Optimizer tab s Engine LSQ options to do SO Profile Settings Engine The LSQ Engine uses a gradient based algorithm which optimizes a circuit through a series of incremental adjustments towards a goal Curve Fit Error Reference Only Uses only reference file data points for error calculation Cancel Set Defaut Optimizer Monte Carlo Smoke Simulation Sensitivity Pertubation Size Abs Fune Convergence Tol Rel Func Convergence Tol Convergence Tol False Convergence Tol Min Factor to Inc Trust Region Max Factor to Inc Trust Region Max Number of Trial Runs To view and change the default options 1 0 005 1 0e 20 1 0e 10 1 0e 4 1 0e 14 A LUTEA Help i From the Advanced Analysis Edit menu select Profile Settings Click the Optimizer tab and select LSQ from the Engine drop down list Edit def
55. parameter names for semiconductor components The table is sorted in alphabetical order according to parameter names that will display in the Smoke results Smoke Parameter Name and Symbol Semiconductor Property Name Component Maximum Operating Condition IB BJT Maximum base current A IC BJT Maximum collector current A PDM BJT Maximum power dissipation W RCA BJT Thermal resistance Case to Ambient degC W RJC BJT Thermal resistance Junction to Case degC W SBINT BJT Secondary breakdown intercept A SBMIN BJT Derated percent at TJ secondary breakdown SBSLP BJT Secondary breakdown slope SBTSLP BJT Temperature derating slope secondary breakdown 156 PSpice Advanced Analysis Users Guide Product Version 10 5 Smoke Parameter Name and Symbol Semiconductor For power users Property Name Component Maximum Operating Condition TJ BJT Maximum junction temperature degC VCB BJT Maximum collector base voltage V VCE BJT Maximum collector emitter voltage V VEB BJT Maximum emitter base voltage V IF Diode Maximum forward current A PDM Diode Maximum power dissipation W RCA Diode Thermal resistance Case to Ambient degC W RJC Diode Thermal resistance Junction to Case degC W TJ Diode Maximum junction temperature degC VR Diode Maximum reverse voltage V IC IGBT Maximum collector current A IG IGBT Maximum gate current A PDM IGBT Maximum Power dissipation W RCA IGBT Thermal res
56. running any kind of analysis other than a single point sweep analysis A goal function computes a single number from a waveform This can be done by finding a characteristic PSpice Advanced Analysis Users Guide 77 Chapter 4 Optimizer Optimizer expression 78 Product Version 10 5 point e g time of a zero crossing or by some other operation For example you can use a goal functions to m Find maxima and minima in a trace m Find distance between two characteristic points such as peaks m Measure slope of a line segment m Derive aspects of the circuits performance which are mathematically described such as 3 dB bandwidth power consumption and gain and phase margin To write effective goal functions determine what you are attempting to measure then define what is mathematically special about that point or set of points Note Be sure that the goal functions accurately measure what they are intended to measure Optimization results highly depend on how well the goal functions behave Discontinuities in goal functions i e sudden jumps for small parameter changes can cause the optimization process to fail An expression defines a design characteristic The expression is composed of optimizer parameter values constants and the operators and functions shown in Table 4 1 For example To measure the sum of resistor values for two resistors with parameterized values named R1val and R2val respectively us
57. space but this can be changed by modifying component values The LSQ engine and you as the user do not have an eagle s eye view of the terrain such as the topographic map figure above gives us Instead the terrain is completely fogged in The engine is set at a starting point without prior knowledge of the topography It must search for the bottom of a valley local minimum by feeling its way with trial runs and only taking steps that move downhill The valley it moves into depends on the starting parameter values and the contour of the design space Your search objective is to find the optimum solution This may be the global minimum However if factors such as cost and manufacturability are considered the optimum solution may be another local minimum with an acceptable total error Finding the optimum result may require extensive searches with starting points widely distributed over the design space This is especially true in complex schematics with numerous parameters Before each step the LSQ engine does a sensitivity run for each parameter These runs are essentially tiny steps in the Parameter A and Parameter B directions From the up or down movement found in each direction the LSQ engine estimates the downhill direction or direction of steepest descent It then takes a step in that direction Sensitivity 0 3 0 0 7 Sensitivity 0 0 3 0 5 A B E A 0 0 0 TRIAL STEP PSpice Advanced Analys
58. the irs enc part is parameterized 2 Use the Add Library browse button to add the pspice elem library from the advanls folder to the Libraries text box 3 Select Resistor and click OK The resistor appears on the schematic PSpice Advanced Analysis Users Guide Product Version 10 5 Example Setting a parameter value 1 Double click on the Resistor symbol The Property Editor appears Note the Advanced Analysis parameters already listed for this component i 3t Distribution i J CMTC PAE parameter Smoke parameter Tolerance parameters ia ee E i F cunt ui L rat ATL PEE FELA SIRE i pei Baldini zie parameters xo RAE Optimizable oes m parameter A mcum M i Smoke Tr we bn Ma Min on parameter A vim ti ee _ TiM aaa 2 Verify that all the parameters required for Sensitivity Optimizer Smoke and Monte Carlo are visible on the symbol Refer to the tables in Adding additional parameters on page 32 Set the resistor VALUE parameter to 10k 4 Settheresistor POSTOL parameter to RTOL PSpice Advanced Analysis Users Guide 37 Chapter 2 Libraries Using the design variables table Product Version 10 5 Set the resistor parameter values using the design variables table We ll do one parameter for this resistor 1 Select the Variables part from the PSpice SPECIAL library Part ven ABLES Part List m i Cancel
59. the new file button in the Discrete Files text box browse to the new table file you have created and select it 5 Click in the Discrete Table Alias text box Advanced Analysis places the file alias name in the text box 6 Inthe Part Type text box select the part for which the new discrete value table is created In case the discrete value table is not for Resistor inductor or capacitor select Other from the drop down list 7 Click OK You can now use the information stored in the new table file Using the table 1 Inthe Advanced Analysis Optimizer view select Discrete from the toolbar engine drop down list The Discrete Table column gets added in the Parameters table 2 Inthe Discrete Table column select the required table from the drop down list Device Level Parameters What are device level parameters The devices are constructed as parameterized models that allow passing of parameters from the instance of the device During optimization you can also vary the device level parameters of a component To add device level parameters of a component to the parameter table in the Advanced Analyses Optimizer complete the following tasks m Add device level parameters as instance properties PSpice Advanced Analysis Users Guide 133 Chapter 4 Optimizer Product Version 10 5 m Export these properties to Advanced Analysis optimizer Adding Device level parameters as instance properties 1 Select the componen
60. the period over which you want to average In Smoke click I on the top toolbar and wait for the new values to appear The information is provided this way for user convenience to show all calculated simulation values average RMS and peak but comparison to limits requires user interpretation The color coding is intended to help 315 Chapter 10 Troubleshooting Problem Results are not what you expected Possible cause Product Version 10 5 Solution The derating factor for the PDM smoke parameter isn t 100 even though I m using No Derating My Optimizer results don t look right The current results are missing In Optimizer finally get a good parameter value but as continue optimizing other things the good parameter value keeps changing In Optimizer there aren t any discrete values listed for my component Can t see the Optimizer discrete tables column can t find my individual Monte Carlo run results want more detail on my Monte Carlo graph 316 This is OK Smoke applies a thermal correction to the calculation Your cursor might be set ona prior run in the Error Graph The results you see are history The good parameter value needs to be locked in so it won t change for the next runs Discrete values tables are provided for RLCs If your component is not an RLC you ll have to create a discrete values table Optimizer engine is not set to Discre
61. to perform specific analyses Advanced Analysis provides help in two ways automatically AutoHelp and manually AutoHelp is embedded in its own window and automatically displays help topics that are associated with your current activity as you move about and work within the Advanced Analysis workspace and interface It provides immediate access to information that is relative to your current task but lacks the complete set of navigational tools for accessing other topics The manual method lets you open the help system in a separate browser window and gives you full navigational access to all topics and resources outside of the help system Using either method help topics include Explanations and instructions for common tasks Descriptions of menu commands dialog boxes tools on the toolbar and tool palettes and the status bar Glossary terms Reference information Product support information An online searchable user s guide An online searchable library list for PSpice model libraries An online searchable reference manual for the PSpice simulation software products Concise descriptions of the commands shortcuts and tools available in PSpice An online searchable user s guide PSpice Advanced Analysis Users Guide Product Version 10 5 Related documentation This documentation component Provides this OrCAD Capture Quick Reference Card Concise descriptions of the commands shortcuts
62. tolerances using this table RF Amplifier 00 Tok raices CTOL 10 RTOL 10 LTOL 0 VTOL 0 ITOL 0 User Varebks f In i I INI cM TRAN Sin sm Men acei a be o 0 0 3 Select the SCHEMATIC1 AC simulation profile 54 PSpice Advanced Analysis Users Guide Product Version 10 5 Sensitivity procedure The AC simulation included with the RF example Simulation Settings AC E x General Analysis Configuration Files Options Data Collection Probe Window Analysis type AC Sweep Type Linear Start Frequency f k Options Logarithmic End Frequency fi G S Decade z Points Decade fio Monte Carlo Worst Case Parametric Sweep Noise Analysis Temperature Sweep Save Bias Point Iv Enabled Output Voltage viLoad Load Bias Point lA Source M Interval r Output File Options Include detailed bias point information for nonlinear controlled sources and semiconductors OP Cancel Help 1 Click to run the simulation 2 Review the results tf_amp SCHEMATIC1 ac dat active 5 6nU 2 5nU Bu 8 4 t m bra 18KHZ 188KHZz CRET Figure 1 BMHZ 1 BHHZ 188HHz mra Frequency The waveforms are what we expected Measurement Measurement In the simulator m m maoa view measurement L M _ bandwidth v load 3 results LE Ww miniog Q v inoiseJ v inoise 8 28 max v onoise The mea
63. two types of specifications Measurement specifications should be used in cases where circuit performance is measurable in terms of variable parameter values such as gain margin for the circuit Curve fit specifications should be used in cases where circuit output is a waveform such as in wave shaping circuits Setting up measurement specifications In the Advanced Analysis Optimizer you can specify the measurement specification in the Standard tab 1 In the Specifications table click on the row containing the text Click here to import The Import Measurements dialog box appears with measurements configured earlier in PSpice Highlight the measurements you want to vary and click OK The components are now listed in the Specifications table Specify the acceptable minimum and maximum measurement values in the Specifications table Min and Max columns If you are using the Modified LSQ engine mark the measurement as a goal or constraint by clicking in the Type column PSpice Advanced Analysis Users Guide 87 Chapter 4 88 Optimizer Product Version 10 5 The engine strives to get as close as possible to the goals while ensuring that the constraints are met Weigh the importance of the specification using the Weight column Change the number in the weight column if you want to emphasize the importance of one specification with respect to another Use a positive integer greater than or equal
64. values The normal flow in which these engines are used is Random engine followed by LSQ or MLSQ engine and finally the Discrete engine To know more about the Optimizer engines see Engine overview From the top toolbar engine drop down list select one of the four optimizing engines Note The Discrete engine is used at the end of the optimization cycle to round off component values to commercially available values Setting up component parameters 84 In this step you identify the components or the parts in the circuit whose parameter values you need to vary Though the Optimizer in Advanced Analysis can support any number of components it is recommended that the number of components with the variable parameter values should be kept to minimum You can specify parameters using BH Schematic Editor m Optimizer H Sensitivity Schematic Editor 1 In the schematic editor select the component whose parameter values you want to vary 2 Select PSpice gt Advanced Analysis gt Export Parameters to Optimizer The component gets added in the Parameters table PSpice Advanced Analysis Users Guide Product Version 10 5 Optimizer procedure overview Note After you select the component you can right click and select Export Parameters to Optimizer from the pop up menu This command is enabled only if the selected component is based on PSpice provided templates Optimizer 1 Inthe Parameters table in A
65. voltages currents power digital data noise data and all of these for internal subcircuit components results in a large data file and large memory use Note You can also place markers on nets pins and devices on the schematic and collect data at these marker locations In PSpice set the data collection option to At Markers Only for all the data types you want See the schematic editor help for more information on how to use markers on the schematic Limit data collection to only the information that is needed to perform Advanced Analysis You can do this in conjunction with the data file solution mentioned on the previous page or do just this and save data for all Monte Carlo runs To change data collection options for each simulation do the following for each simulation profile used in Advanced Analysis 1 From the PSpice Simulation menu select Edit Profile 2 In the Simulation Settings dialog box select the Data Collection tab 3 Set the data collection option to None for all the data types that are not required Use the drop down list to select the option 4 Set the data collection option to All but Internal Subcircuits for data required for Advanced Analysis Use the drop down list to select the option PSpice Advanced Analysis Users Guide 319 Chapter 10 Troubleshooting Product Version 10 5 320 PSpice Advanced Analysis Users Guide Property Files A PSpice A DAMS has an a
66. 07 Chapter 6 Monte Carlo Product Version 10 5 Storing simulation data If you are planning an analysis of thousands of runs ona complex circuit you can turn off the simulation data storage option to conserve disk space To turn off data storage 1 From the Advance Analysis menu select Edit Profile Settings Simulation 2 Fromthe Monte Carlo field select Save None The simulation data will be overwritten by each new run Only the last run s data will be saved 3 From the Advance Analysis menu select Edit Profile Settings Simulation rf_amp SCHEMATIC1 PSpice Adya File Edit View Run Analysis Windi s m Undo CHTEZ Redo Gtr ad Gut GrEX Copy Grec amp Paste Ciro Del Advanced Analysis Optimizer Monte Carlo Smoke Simulation r Data Collection Sensilivity Save All Runs Optimizer Save All Runs 7 Monte Carlo Note These settings allow the user to control the amount of data stored in the simulation results data file Cancel Help 208 PSpice Advanced Analysis Users Guide Product Version 10 5 4 Example From the Monte Carlo field select Save None The simulation data will be overwritten by each new run Only the last run s data will be saved Changing components or parameters When running other examples if you do not get the results you want go to the schematic editor and change circuit information 1 Printing re
67. 1 41e 009 trise Discrete Values 1e 009 5e 009 16 008 tfall VALUE VALUE Linear Start1e 010 End 1e 009 Step 4e 01 lw Cancel The changes are reflected in the Sweep Parameters window Sweep Parameters On Off Component Parameter Sweep Variable Sweep Type Sweep Values Start 1e 010 End 1e 009 iinner3 Click here to import a EN from the design pro Besides the values entered by you in the Select Sweep Parameters dialog box the Sweep Variable column also gets populated Parametric Plotter assigns variables to the parameters depending on the order in which they are added If required you can change this order 230 PSpice Advanced Analysis Users Guide Product Version 10 5 Example Add measurements To evalute the influence of varying parameter values on the overshoot and power disspipation across resistor R3 and to include a trace add these three as the measurement expressions to be evaluated 1 Inthe Measurements tab select Click here to add a measurement created in PSpice row 2 Inthe Import Measurement s dialog box select Overshoot V 11 2 yatlastX AVG W R2 and v q1 d from the transient sim profile 3 Click OK The measurements get added to the Measurements tab E Measurements 1 Results Erot Information Measurements Profile Measurement Min Value Max Value Run sweep analysis Torun the sweep analysis click the Start gt button on the toolbar PSpice Advanced A
68. 1 8KHz 18KHz 188KHz 1 8HHz 18HHz fe db U Load Frequencu Resolving the optimization 7 5797 E 6 3081 13 888 PIE 188HHz 1 8GHz One solution may be to introduce a specification that keeps the low frequency cutoff above 1kHz but this would complicate the optimization and take longer to complete Another solution may be to simplify things It could be that we have given the optimizer too many degrees of freedom parameters some of which may not be necessary for meeting our goals Let s check out the bandwidth measurement in Sensitivity to see which components are the most sensitive PSpice Advanced Analysis Users Guide 305 Chapter 10 Troubleshooting Product Version 10 5 Sensitivity check 1 Return to Advanced Analysis and from the View menu select Sensitivity The Sensitivity tool opens 2 Make sure Rel Sensitivity is displayed in the Parameters table If you need to change the display from absolute to relative sensitivity a Right click and from the pop up menu choose Display Relative Sensitivity Parameters Linear Find in Design Display Absolute Sensitivity Bar Graph Style gt m Relative Sensitivity Send To Optimizer 3 Inthe Specifications table select the bandwidth measurement second row Specifications Measurement EIN A ane schematic1 ac sim max v onoise Click here to import a measurement created within PS 4 Click I on the top toolbar to start th
69. 10 log1Q v inoise v inoise 8 28e 19 Click here to import a measure 3 Inthe Max DB V Load row of the Specifications table Q M Min column type in a minimum dB gain of 5 Q Max column type in a maximum dB gain of 5 5 Q Type column click in the cell and change to Constraint Q Weight column type in a weight of 20 4 Inthe Bandwidth V Load 3 row Q M Min column type in a minimum bandwidth response of 200e6 Q Max column leave empty unlimited Q Type column leave as a Goal Q Weight column leave the weight as 1 5 Inthe Min 10 log10 v in row a Min column leave empty Q Max column type in a maximum noise figure of 5 Q Type column click in the cell and change to Constraint Q Weight column leave the weight as 1 6 Inthe Max V onoise row a M Min column leave empty Q Max column type in a maximum noise gain of 3n Q Type column click in the cell and change to Constraint PSpice Advanced Analysis Users Guide 115 Chapter4 Optimizer Product Version 10 5 Q Weight column type in a weight of 20 Note For information on numerical conventions Numerical conventions on page 20 Click a cell to get a drop down list and select Goal Specifications Next Run Profile Measurement mu v AEE imsx elotv load Ls saucer 3 LL v al E2 rt_amp schemstict loandwidth v load 3 zx Dow p L v Te rcome schemetict nincto togtGCatnoisevncise rs 266 19 A Es ensi 3 L v l
70. 28 for details The Advanced Analysis libraries contain parameterized and standard components The majority of the components are parameterized Standard components in the Advanced Analysis libraries are similar to components in the standard PSpice libraries and will not be discussed further in this document PSpice Advanced Analysis Users Guide 23 Chapter 2 Product Version 10 5 Parameterized components 24 A parameter is a physical characteristic of a component that controls behavior for the component model In Capture a parameter is called a property A parameter value is either a number or a variable When the parameter value is a variable you have the option to vary its numerical solution within a mathematical expression and use it in optimization Design EntryWhen the parameter value is a variable you have the option to vary its numerical solution within a mathematical expression and use it in optimization In the Advanced Analysis libraries components may contain one or more of the following parameters B Tolerance parameters For example for a resistor the positive tolerance could be POSTOL 10 m Distribution parameters For example for a resistor the distribution function used in Monte Carlo analysis could be DIST FLAT M Optimizable parameters For example for an opamp the gain bandwidth could be GBW 10 MHz NH Smoke parameters For example for a resistor the power maximum operating condition
71. Absolute to Relative sensitivity 1 Right click anywhere in the Parameters table 2 Select Display Absolute Sensitivity or Relative Sensitivity from the pop up menu Note See Sensitivity calculations on page 66 Changing bar graph style from linear to log Most of the sensitivity values can be analyzed using the linear scale Logarithmic scale is effective for analyzing the smaller but non zero sensitivity values To change the bar graph style 1 Right click anywhere in the Parameters table 2 Select Bar Graph Style Linear or Log from the pop up menu d Important If X is the bar graph value on a linear scale then the bar graph value on the logarithmic scale is not log X The logarithmic values are calculated separately Interpreting lt MIN gt results Sensitivity displays lt MIN gt on the bar graph when sensitivity values are very small but nonzero Interpreting zero results Sensitivity displays zero in the absolute relative sensitivity and bar graph columns if the selected measurement is not sensitive to the component parameter value PSpice Advanced Analysis Users Guide 49 Chapter 3 Sensitivity Product Version 10 5 Controlling Sensitivity Data cells with cross hatched backgrounds are read only and cannot be edited The graphs are also read only Pausing stopping and starting Pausing and resuming 1 Click JJ on the top toolbar The analysis stops available data is displayed and the
72. Guide Product Version 10 5 Optimizer procedure overview Assigning available values with the Discrete engine The Discrete engine is used at the end of the optimization cycle to round off components to commercially available values 1 From the top toolbar engine field select Discrete from the drop down list A new column named Discrete Table appears in the Parameters table For each row in the Parameters table that contains an RLC component click in the Discrete Table column cell An arrow appears indicating a drop down list of discrete values tables Select from the list of discrete values tables A discrete values table is a list of components with commercially available numerical values These tables are available from manufacturers and several tables are provided with Advanced Analysis Click b The Discrete engine runs The Discrete engine first finds the nearest commercially available component value in the selected discrete values table Next the engine reruns the simulation with the new parameter values and displays the measurement results At completion the Current column in the Parameters table is filled with the new values Return to your schematic editor and put in the new values See Finding components in your schematic editor While you are still in your schematic editor rerun the simulation Check your waveforms and measurements in PSpice and make sure they are what you expect
73. L_ON_OFF property In the schematic design attach the TOL_ON_OFF property to the device instance for which you do not want to perform the Sensitivity and MonteCarlo analysis Set the value of the TOL_ON_OFF property to OFF When you set the property value as OFF the tolerances attached to the component parameters will be ignored and therefore the component parameters will not be available for analysis Reviewing Monte Carlo data You can review Monte Carlo results on two graphs and two tables m Probability density function PDF graph m Cumulative distribution function CDF graph W Statistical Information table in the Statistics tab a Raw Measurements table in the Raw Meas tab Reviewing the Statistical Information table 180 For each run Monte Carlo randomly varies parameter values within tolerance and calculates a single measurement value After all the runs are done Monte Carlo uses the run results to perform statistical analyses PSpice Advanced Analysis Users Guide Product Version 10 5 Column heading Monte Carlo procedure 1 Click the Statistics tab to bring the table to the foreground 2 Select a measurement row in the Statistical Information table A black arrow appears in the left column and the row is highlighted The data in the graph corresponds to the selected measurement only You can review results reported for each measurement Means Cursor Min Cursor Max Yield in percen
74. Log File Monte Carlo to see parameter values and other details m rf amp SCHEMATI 1 PSpice Advanced Analysis Monte Carlo File Edit View Run Analysis Window Help B e xi m exu preces of zi nm A5 amp e Probability Density Graph Runs 1 to 100 RursusrssUSssssaUEEuHNNSHA VEU Number of Runs Q8 89 9 9 1 92 93 9 4 95 96 97 98 99 10 10 40 2 10 3 10 4 10 5 10 6 10 7 10 8 max db v load 8 3 84 85 86 87 El Statistig EE Raw meas Statistical Information On Off Profile Measurement Std Dev 3Sigma 6Sigma Median gt Bd rf amp max db v load 8 3900 10 8181 1t E 0109m 101 106 9 41 INdwidth v ldgd 3 139 9560meg 154 4402meg Pe Bg iame maosna 37219 46057 e B iamen N 38695 aoon EN FOS Click here to import a measurement created within PSpice gl d BEI Carlo Ss A fMonte carlorans9conpeted NE relfomear N Oo E The selected measurement s min Click Raw Meas tab for 100 run results max and other run results are plotted on the PDF graph Reviewing Monte Carlo data The Statistics tab is already in the foreground and the Statistical Information table contains results for the four imported measurements Select the Max DB V load measurement row A black arrow appears in the left column and the row is highlighted The values in the PDF graph correspond to this measurement PSpice Advanced Analysis Use
75. O PSpice Optimizer Optimizer is a design tool for optimizing analog circuits and their behavior It helps you modify and optimize analog designs to meet your performance goals PSpice Advanced Analysis Users Guide 71 Chapter 4 72 Optimizer Product Version 10 5 Optimizer fine tunes your designs faster and automatically than trial and error bench testing can Use Optimizer to find the best component or system values for your specifications Advanced Analysis Optimizer can be used to optimize the designs that meet the following criteria m Design should simulate with PSpice You can optimize a working circuit design that can be simulated using PSpice and the simulation results are as desired m Components in the design must have variable parameters each of which relates to an intended performance goal Optimizer cannot be used to m Create a working design M Optimize a digital design or a design in which the circuit has several states and small changes in the variable parameter values causes a change of state For example a flip flop is on for some parameter value and off for a slightly different value You can use the Advanced Analysis Optimizer to import legacy Optimizer projects For view the detailed procedure see the technical note posted on the OrCAD community site www orcadpcb com All PSpice related technical notes posted on the community site are available under Application Notes section of the PSpice pa
76. PRINTDGTLCHG SUBPARAM Remove Library VECTOR1 VECTORI6 D CADENCE141 CAPTURESLIBRARY PSPICE SPECIAL OLB farch VECTOR2 VECTOR32 X Help E Nm rd Note tool tip Libraries Graphic 4 i Design Cache Normal with the library PSPICE ELEM c onver path name Packaging Parts per Pkg 1 Bat j z Type Homogeneous Tok raices Smoke Limits TOL RMAX 0 25 Bro RSMAX 0 005 TOL RTMAX 200 VTOL 0 VMAX 12 ITOL 0 CMAX 50 CBMAX 125 Double click on UserVarlbks CSMAX 0 005 R CTMAX 125 variable name to edi M CIMA 1 LMAX 5 value DSMAX 300 IMAX 1 Double click on the RTOL number 0 in the design variables table PSpice Advanced Analysis Users Guide Product Version 10 5 For power users The Display Properties dialog box appears Edit value from 0 to Name RTOL ao i j i omm Change IiseDerau Display Format m En s C Do Not Display or f Value Only Default m un gt Rotation im C Name Only Gy rw p i Click OK Both if Value Exists C sp F am ma Edit the value in the Value text box 4 Click OK The new numerical value will appear on the design variable table on the schematic Advanced Analysis will now use the resistor with a positive tolerance parameter set to 1096 If we added more resistors to this design we could then set the POSTOL resistor parameter values to RTOL and each resistor would immediately apply the 10 v
77. PSpice Advanced Analysis User s Guide Product Version 10 5 July 2005 1995 2005 Cadence Design Systems Inc All rights reserved Printed in the United States of America Cadence Design Systems Inc 555 River Oaks Parkway San Jose CA 95134 USA Trademarks Trademarks and service marks of Cadence Design Systems Inc Cadence contained in this document are attributed to Cadence with the appropriate symbol For queries regarding Cadence s trademarks contact the corporate legal department at the address shown above or call 800 862 4522 All other trademarks are the property of their respective holders Restricted Print Permission This publication is protected by copyright and any unauthorized use of this publication may violate copyright trademark and other laws Except as specified in this permission statement this publication may not be copied reproduced modified published uploaded posted transmitted or distributed in any way without prior written permission from Cadence This statement grants you permission to print one 1 hard copy of this publication subject to the following conditions 1 The publication may be used solely for personal informational and noncommercial purposes 2 The publication may not be modified in any way 3 Any copy of the publication or portion thereof must include all original copyright trademark and other proprietary notices and this permission statement and 4 Cadence reserves the rig
78. Q engine uses a gradient based algorithm that optimizes a circuit by iteratively calculating sensitivities and adjusting parameter values to meet the specified goals Modified LSQ engine The Modified LSQ engine uses both constrained and unconstrained minimization algorithms which allow it to optimize goals subject to nonlinear constraints The Modified LSQ engine generally runs faster than the LSQ engine because it runs a reduced number of incremental adjustments toward the goal When using the Modified LSQ engine you can set your measurement specifications as goals or constraints The engine strives to get as close to the goals as possible while ensuring that the constraints are met Random engine The Random engine randomly picks values within the specified range and displays misfit error and parameter history Discrete engine The Discrete engine is used at the end of the optimization cycle to round off component values to the closest values PSpice Advanced Analysis Users Guide 135 Chapter 4 Optimizer Product Version 10 5 available commercially Typically once you have optimized your circuit you will most likely want to convert your component values into real world parts For example the Optimizer determines that the 3K resistor in the RF amplifier circuit should be 2 18113K but you cannot use this value in your manufactured design You can then specify a discrete table and switch to the Discrete Engine The Di
79. Type Sweep Values i Click here to import a parameter from the design property map Figure 7 3 Setting sweep parameters PSpice Advanced Analysis Users Guide 217 Chapter 7 Parametric Plotter Product Version 10 5 The value of the sweep variable is an indication of how parameters will be varied during sweep analysis Sweep Variables values are assigned in the order in which sweep parameters are defined If required you can change these values While modifying the values of Sweep Variable ensure that each parameter has a unique value of sweep variable attached to it Also the values should follow the sequence For example if you select three parameters to be varied during the sweep analysis the sweep variables should have values as outer innerl and inner2 You cannot have random values such as innerl inner2 and inner4 For the sweep analysis the values of parameters is varied in nested loops For example if you select two variables the outer variable is fixed for the analysis while the inner variable goes through all of its possible values The outer variable is then incremented to its next value and the inner variable again cycles through all of its possible values This process is continued for all possible values of the outer variable The result for each run of the analyzer appears in the Results pane By default the results are displayed in the order described above NA TQ Tip Similar process is
80. Usage of different sections of a property file Statements Sections in Used in the property file model params Optimization Monte Carlo analysis Sensitivity analysis POSTOL and Monte Carlo analysis REGION Sensitivity analysis DERATE_TYPE Smoke analysis smoke section Smoke analysis max_ops Smoke analysis The model info section A part of the TEMPLATES PRP file containing the model info section for an OPAMP model is shown below 739 model info SYMBOL TYPE 39 DEFAULT SYMBOL 5 Pin Opamp NAME FET Input Opamp W spice_dsg ygu W mode lt ype W M The first line in a template property file specifies the model template number The model template number is used as a reference in the device property file to locate the generic model definition in the template property file The model info section contains information such as symbol type default symbol symbol name spice designator and PSpice Advanced Analysis Users Guide 325 Chapter A Property Files Product Version 10 5 model type Spice designator indicates the type of PSpice device For example the spice designator for an template based diode model is X and the spice designator for the diode model based on device characteristic curves is D Similarly the model type can be either M for macro models or P for primitive models The model_params section 326 The model_params section lists all simulation parameters al
81. a G Press OF when done viewing 11 Click Close Viewing the results of measurement evaluations 1 From the View menu select Measurement Results 246 PSpice Advanced Analysis Users Guide Product Version 10 5 Example The Measurement Results table displays below the plot window View Simulation Trace Plot Tools Wwindc Zoom ES Measurement Results al Circuit File Gg Output File EI Simiilahinn Rezilta 2 Click the box in the Evaluate column A checkmark appears in the Evaluate column checkbox and the PSpice calculation for your measurement expression appears in the Value column 1 GKHZ 18KHz 166KHZ 1 8HHz Noise Figure Frequency Measurement Results Evaluate Measurement joe Max DBrv load 941802 s Measurement definitions included in PSpice Definition Finds the Bandwidth Bandwidth of a waveform you choose dB level Bandwidth_Bandpass_3dB Bandwidth 3dB level of a waveform Bandwidth Bandpass 3dB XRang Bandwidth 3dB level of a waveform over e a specified X range CenterFrequency Center frequency dB level of a waveform PSpice Advanced Analysis Users Guide 247 Chapter 8 Measurement Expressions Definition Product Version 10 5 Finds the CenterFrequency_XRange ConversionGain ConversionGain_XRange Cutoff Highpass 3dB Cutoff Highpass 3dB XRange Cutoff Lowpass 3dB Cutoff Lowpass 3dB XRange DutyCycle DutyCycle XRange Falltime NoOversho
82. actor of four 400 100 Note In all gears except the legacy gear error is calculated for all the sweep points that are overlapping between the output wave form and the reference waveform Using curve fitting to optimize a design 1 Open a Capture project opj and simulate it Verify that circuit is complete and is working fine 2 Invoke Advanced Analysis Optimizer select the Curve Fit tab 3 Create a curve fit specification Specify the following a Trace Expression Select a simulation profile and add a trace expression b Name and location of the Reference file c Reference waveform as specified in the reference file d Tolerance PSpice Advanced Analysis Users Guide 97 Chapter 4 Optimizer Product Version 10 5 e Weight 4 Select the optimizable parameters For each parameter the original value the min value original value 10 and the max value original value 10 displays automatically You can change the min max range as per the requirement 5 Specify the method for error calculation a From the Edit menu choose Profile Settings b From the Curve Fit Error drop down list in the Optimizer tab of the Profile Settings dialog box select the method to be used for the error calculation To know more about error calaculation methods see Error Calculation on page 93 6 Specify whether or not you want to store simulation data a In the Profile Settings dialog box select the Simulation tab
83. actors In your custom derating file enter the derating factors as decimal percents in double quotes For the example below if the resistor had a power dissipation PDM maximum operating condition of 5W the 9 derating PSpice Advanced Analysis Users Guide Product Version 10 5 For power users factor tells Advanced Analysis to use 0 9 x 5 4 5W as this resistor s safe operating limit RES PDM 1 TMAX 1 TB 1 Figure 5 2 Resistor smoke parameters and derating factors in a portion of a custom derating file Creating a new custom derate file Advanced Analysisprovides you the capability to create and edit derate files You can perform this operation by using the Edit Derate File dialog box Edit Derate File x Derate File D 4PSpice samplesample drt r Device Types Derating Factors Click here to add device Click here to add derating factor 1 Tocreate a new derate file from scratch click the Create Derate File button Custom Derating Files PSpice Advanced Analysis Users Guide 161 Chapter 5 Smoke Product Version 10 5 The Edit Derate File dialog box appears Edit Derate File x Derate File Derate Types r Derating Factors Click here to add derating factor In the Edit Derate Type dialog box type the derate type and select the corresponding device category The derate type can be any user defined value 2 Toadda new derate type click the Click here to
84. add a device row A blank row gets added in the Derate Types pane 3 Inthe Derate Types text box enter myderatetype Derating Factors Derate Types Click here to add derating factor nyderatetype jt Click here to add device 4 Click the Device Category grid 162 PSpice Advanced Analysis Users Guide Product Version 10 5 For power users 5 From the drop down list box select RES Derating Factors Derate Types myderatetype Click here to add derating factor myderatetype is the derate type for a resistor of type RES 6 To specify the derate values for various resistor parameters click the Click here to add derating factor row in the Derating Factors window A blank row gets added Derating Factors Derate Types myderatetype PSpice Advanced Analysis Users Guide 163 Chapter 5 Smoke Product Version 10 5 7 Select the derate factor from the Factor drop down list r Derate Types r Derating Factors Derate Types Device Category myderatetype Click here to add device Herating factor The corresponding value for the derate factor is automatically filled in Derate Types Derating Factors X X Derate Types Device Category myderatetype Click here to add device Cickhereioaddderaingfacior 8 Modify the value of the derate factor as per the requirement 9 Similarly specify additional derate types and their c
85. ads Ohms Henrys volts and amperes It adds the units automatically depending on the context Name Numerical User Example value types in Or Uses femto 10 15 F f 1e 15 2f 2F 2e 15 pico 1012 Pp 1e 12 40p 40P 40e 12 nano 10 N n 1e 9 70n 70N 70e 9 micro 106 U u 1e 6 20u 000001 20U 20e 6 milli 103 M m 1e 3 30m 001 30M 30e 3 03 kilo 10 K k 1e 3 2k 1000 2K 2e3 2e 3 2000 20 PSpice Advanced Analysis Users Guide Product Version 10 5 Numerical conventions Name Numerical User value types in Example Uses mega giga tera 106 MEG 1 000 000 eg 10 G g 1072 Ti 1e 6 1e 9 1e 12 20meg 20MEG 20e6 20e 6 20000000 25g 25G 25e9 25e 9 30t 30T 30e12 30e 12 PSpice Advanced Analysis Users Guide 21 Chapter 1 Introduction Product Version 10 5 22 PSpice Advanced Analysis Users Guide Libraries In this chapter Overview on page 23 Using Advanced Analysis libraries on page 27 Preparing your design for Advanced Analysis on page 30 Example on page 36 For power users on page 39 Overview PSpice ships with over 30 Advanced Analysis libraries containing over 4 300 components Separate library lists are provided for Advanced Analysis libraries and standard PSpice libraries The components in the Advanced Analysis libraries are listed in the Advanced Analysis library list See Using the online Advanced Analysis library list on page
86. ailable data is displayed and the last completed run number appears in the output window 1 Click the depressed If or to resume calculations Stopping A Click Bi on the top toolbar If a Monte Carlo analysis has been stopped you cannot resume the analysis Starting Click to start or restart Changing circuit components or parameters If you do not get the results you want you can return to the schematic editor and change circuit parameters 1 Try a different component for the circuit or change the tolerance parameter on an existing component Rerun the PSpice simulation and check the results Rerun Monte Carlo using the settings saved from the prior analysis Review the results PSpice Advanced Analysis Users Guide 185 Chapter 6 Monte Carlo Product Version 10 5 Controlling measurement specifications Printing results 186 If you do not get the results you want and your design specifications are flexible you can add edit delete or disable a measurement and rerun Monte Carlo analysis Cells with cross hatched backgrounds are read only and cannot be edited To exclude a measurement from the next optimization run click the ya in the Statistical Information table which removes the check mark To edit a measurement click on the measurement you want to edit then click EJ To edit a measurement specification Min or Max click the minimum or maximum cursor on the graph the selected cur
87. ainst corresponding safe operating limits Safe operating limits Smoke will help you determine B Breakdown voltage across device terminals Maximum current limits Power dissipation for each component Secondary breakdown limits Junction temperatures Smoke is useful as a final design check after running Sensitivity Optimizer and Monte Carlo or you can use it on its own for a quick power check on a new circuit Smoke requires B Components that are Advanced Analysis ready See Chapter 2 Libraries See Smoke parameters on page 154 for lists of parameter names used in Advanced Analysis Smoke PSpice Advanced Analysis Users Guide Product Version 10 5 Smoke procedure B Aworking circuit schematic and transient simulation m Derating factors Smoke uses no derating as the default Note See the online Advanced Analysis library list and the PSpice library list for components containing smoke parameter data Workflow Schematic Editor PSpice Advanced Analysis Simulate the circuit with a transient simulation Check waveforms Set up or edit schematic Change components or edit smoke parameter values Are any parameters smoking Print the results Change derating factors These processes are ee explained in your schematic editor or PSpice user guides Smoke procedure Setting up the circuit in the schematic editor Advanced Analysis requires
88. al values B The next run with one parameter varied within tolerance Values are obtained for each measurement View the Log File for parameter values used in each measurement calculation B Subsequent runs with one parameter varied within tolerance mH A minimum worst case run for each measurement m A maximum worst case run for each measurement For our example circuit with 4 measurements and 12 parameters with tolerances Sensitivity performs 21 runs There is one worst case minimum and one worst case maximum run per measurement a 1 12 2x4 21 runs The nominal There are four measurements run using the used in this example original parameter values There is one run for each parameter varied within tolerance We use 12 parameters To see the details of parameter and measurement calculations from the View menu select Log File PSpice Advanced Analysis Users Guide 69 Chapter 3 Sensitivity Product Version 10 5 70 PSpice Advanced Analysis Users Guide Optimizer In this chapter This chapter introduces you to Optimizer its function and the optimization process Optimizer overview Optimizer overview on page 71 Terms you need to understand on page 73 Optimizer procedure overview on page 80 Example on page 107 For Power Users on page 131 Note Advanced Analysis Optimizer is available with the following products O PSpice Advanced Optimizer Option O PSpice Advanced Analysis
89. ality is suspect has potential for spurious peaks or glitches increase the Threshold value to ensure that the optimizer will not get stuck during the run The Modified LSQ Engine implements two general classes of algorithm to measure design performance least squares and minimization These algorithms are applicable to both unconstrained and constrained problems When optimizing for more than one goal the Modified LSQ Engine always uses the least squares algorithm A reliable measure of performance for a design with multiple targets is to take the deviation of each output from its target square all deviations so each term is positive and sum all of the squares The Modified LSQ Engine then tries to reduce this sum to zero This technique is known as least squares Note that the sum of the squares of the deviations becomes zero only if all of the goals are met Another measure of design performance considers a single output and reduces it to the smallest value possible Example Power or propagation delay each of which is a positive number with ideal performance corresponding to zero Single goal optimization settings 286 When optimizing for more than one goal the Modified LSQ Engine always uses the least squares algorithm For a single goal however you must specify the algorithm for the optimizer 1 Doone of the following Q Select the Least Squares option button to minimize the square of the deviation between the
90. alue from the design variables table Note Values set on the component instance override values set with the design variables table For power users Legacy PSpice optimizations For tips on importing legacy PSpice Optimizations into Advanced Analysis Optimizer see our technical note on importing legacy PSpice optimizations Technical notes are posted on the PSPice page of the OrCAD community web site www orcadpcb com PSpice Advanced Analysis Users Guide 39 Chapter 2 Libraries Product Version 10 5 40 PSpice Advanced Analysis Users Guide Sensitivity In this chapter Sensitivity overview on page 41 Sensitivity strategy on page 43 Sensitivity procedure on page 44 Example on page 53 For power users on page 66 Sensitivity overview Note Sensitivity analysis is available with the following products O PSpice Advanced Optimizer Option O PSpice Advanced Analysis Sensitivity identifies which components have parameters critical to the measurement goals of your circuit design The Sensitivity Analysis tool examines how much each component affects circuit behavior by itself and in comparison to the other components It also varies all tolerances to create worst case minimum and maximum measurement values PSpice Advanced Analysis Users Guide 41 Chapter 3 42 Sensitivity Product Version 10 5 You can use Sensitivity to identify the sensitive components then export the components to Optimize
91. amp The circuit is an RF amplifier with 50 ohm source and load impedances It includes the circuit schematic PSpice simulation profiles and measurements Note For a completed example see lt target directory gt PSpice Capture_Samples AdvAnIs RFAmp directory Setting up the circuit in the schematic editor 1 In your schematic editor browse to the RFAmp tutorials directory target directory PSpice tutorial Capture pspiceaa rfamp 2 Open the RFAmp project 144 PSpice Advanced Analysis Users Guide Product Version 10 5 Example The RF amplifier circuit example RF Amplifier TVCC D1 Smoke Limits RMAX 0 25 RSMAX 0 005 RTMAX 200 Tok raices VM AX 12 CTOL 10 CMAX 50 RTOL 10 CBMAX 125 LTOL 0 CSMAX 0 005 VTOL 0 CTMAX 125 ITOL 0 CIMAX 1 LMAX User vartabls OSMAX 300 AE 2N3905 mo ng C6 CAS 3 ni 50 tu 50 V0C Sng 5m 1Meg ota a 70 3 Select SCHEMATIC1 Tran PSpice Advanced Analysis Users Guide 145 Chapter 5 Smoke Running Smoke Starting a run 146 Product Version 10 5 The Transient simulation included in the RF Amp example Simulation Settings Tran Ix Run to time fi Dus seconds TSTOP Options Start saving data after o seconds Transient options General Settings Monte Carlo w orst Case Maximum step size E n seconds Parametric Sweep Temperature Sweep Save Bias Point Load Bias Point Output File Optio
92. analysis symbol property names symbol parameter names and parameter names used in the Smoke user interface This table is sorted in alphabetical order by parameter names that display in the Smoke user interface Smoke User Symbol Variable Interface Maximum Smoke Table Parameter Passive Operating Parameter Default Name Component Condition Name Value CI Capacitor Maximum ripple CIMAX 1A CV Capacitor Voltage rating CMAX 50V IV Current Max voltage VMAX 12V Supply current source can withstand LI Inductor Current rating LMAX 5A LV Inductor Dielectric DSMAX 300 V strength PDM Resistor Maximum RMAX 0 25 W power dissipation of resistor RBA Resistor Slope of power RSMAX 0 005W deg 1 SLOPE dissipation vs C temperature RV Resistor Voltage Rating RVMAX SLP Capacitor Temperature CSMAX 0 005 derating slope V degC TBRK Capacitor Breakpoint CBMAX 125 degC temperature PSpice Advanced Analysis Users Guide 155 Chapter 5 Smoke Product Version 10 5 Smoke User Symbol Variable Interface Maximum Symbol Smoke Table Parameter Passive Operating Property Parameter Default Name Component Condition Name Name Value TMAX Capacitor Maximum MAX_TEMP CTMAX 125 degC temperature TMAX TB Resistor Maximum MAX_TEMP RTMAX 200 degC temperature resistor can withstand VI Voltage Max current CURRENT IMAX 1A Supply voltage source can withstand Internal parameters not shown in user interface The following table lists smoke
93. anced Analysis Optimizer E Eie Edt view Bun Analysis Window Help 181 xl m x e zmas y nom A amp amp e v ue Error Graph Parameters Hext Run 196 Error 0 5 0 Ru Number LL Standard i Curve Fit Specifications Next Run Onoff Profile Measurement Min Max Type Weight Origi Click here to import a measurement created within PSpice ptimizer For Help press F1 je m Click to import measurements The Import Measurements dialog box appears with measurements configured earlier in PSpice Import Measurement s xj Hold down the Profle Measurement CTR L key an d rf amp schematic1 tran sim No measurements found for this profile amp schematic1 ac sim mae db v load click to add T amp schematic1 ac sim bandwidth v load 3 multiple tf_amp schematic ac sim min 10 log10 v inoise v inoise 8 28e 19 p rf amp schematic1 ac sim mams v onoise measurements gt To select multiple items hold down the CTRL key then click each entry Hold down the SHIFT key to select or deselect adjacent items Cancel Help 2 Selectall the AC sim measurements and click OK 114 PSpice Advanced Analysis Users Guide Product Version 10 5 Example The measurements are now listed in the Specifications table Onoff Profile Measurement v iz B rf_amp schematict ac sim max db v load v v4 EZ rf_amp schematict ac sim min
94. arameters controlling perturbation 283 distribution 25 optimizable 24 26 overriding global values 39 sending to Optimizer from Sensitivity 64 setting up 81 setting values 31 smoke 24 26 154 tolerance 24 25 using the schematic editor 32 Parametric Plotter add plot 223 adding expressions 219 adding traces 220 run 220 view plot 225 viewing results 221 part 344 Product Version 10 5 PSpice Advanced Analysis Users Guide PDF graph 181 performance 76 positive sensitivity 48 POSTOL 32 probability distribution function PDF graph 344 Probe goal function 77 See Also goal function Probe trace function problems common solutions to 308 project setup validating the initial project 17 property TOL_ON_OFF 45 property file device 321 333 Template 321 323 R Random engine 287 344 NumRuns option 290 NumSteps option 289 options 289 to 290 Raw Measurements table 184 read only data 102 142 204 Red 148 references auto help 12 related documentation 11 relative sensitivity 60 344 RELTOL option 284 requirements see specifications 76 restricting calculation range 183 S safe operating limits SOLs 345 see also property 24 see measurements 241 Send to Optimizer 65 senitivity positive 48 sensitivity 345 absolute 66 absolute sensitivity 60 allowable PSpice simulations 17 analysis runs 69 July 2005 example 53 import measurements 46 interpreting MIN resu
95. asurement Max The worst case maximum value for the measurement Note To see all the parameter and measurement values used in Sensitivity calculations from the View menu select Log File Changing from Absolute to Relative sensitivity 1 Right click anywhere on the Parameters table 60 PSpice Advanced Analysis Users Guide Product Version 10 5 Sensitivity procedure A pop up menu appears Find in Design Display Absolute Sensitivity Bar Graph Style m Relative Sensitivity Send To Optimizer de GUE Copy al Paste Delete 2 Select Relative Sensitivity Note See Sensitivity calculations on page 66 Changing the bar graph to linear view 1 Right click anywhere on the Parameters table A pop up menu appears Find in Design Display gt Bar Graph Style v Linear Lo Send To Optimizer a db Gut Copy al Paste Delete 2 Select Linear PSpice Advanced Analysis Users Guide 61 Chapter 3 Sensitivity Product Version 10 5 Controlling Sensitivity Pausing stopping and starting Click to start Click to stop fSenstiviy s Teu Click to pause Pausing and resuming 1 Click JJ on the top toolbar The analysis stops available data is displayed and the last completed run number appears in the output window 2 Click the depressed If or to resume calculations Stopping A Click Wi on the top toolbar If a Sensitivity analysis has been stopped you cannot resume the analys
96. asurements created in PSpice or can create new measurements in Advanced Analysis To import measurements 1 Inthe Specifications table click on the row containing the text Click here to import a measurement created within PSpice The Import Measurement s dialog box appears 2 Select the measurements you want to include PSpice Advanced Analysis Users Guide Product Version 10 5 Sensitivity procedure To create new measurements 1 From the Analysis drop down menu choose Sensitivity Create New Measurements The New Measurement dialog box appears 2 Create the measurement expression to be evaluated and click OK Running Sensitivity m Click on the top toolbar The Sensitivity analysis begins The messages in the output window tell you the status of the analysis For more information see Sensitivity calculations on page 66 Displaying run data Sensitivity displays results in two tables for each selected measurement BH Parameters table Q Parameter values at minimum and maximum measurement values Q Absolute Relative sensitivities per parameter Q Linear Log bar graphs per parameter B Specifications table Q Worst case min and max measurement values Sorting data Double click on column headers to sort data in ascending or descending order PSpice Advanced Analysis Users Guide 47 Chapter 3 Sensitivity Product Version 10 5 Reviewing measurement data Select a measurement o
97. ation table Cumulative Distribution Graph Runs 1 to 100 100 i i 50 0 Percent of Runs 84 85 86 87 88 89 9 91 92 93 94 95 96 97 98 99 10 101 102 10 3 10 4 10 5 106 107 10 8 Max DB V Load E Statistics E Raw Meas 9 3962 REZ NN WIEN NRE Cursor Min and Cursor Max data change to reflect nex Yield value changes to reflect new cursor positions min max data Aj Restricting the calculation range To quickly view statistical results for a different min max range use the Restrict Calculation Range command 1 Setthe graph cursors at Min 9 and Max 10 Or Edit the min or max values in the Statistical Information table 202 PSpice Advanced Analysis Users Guide Product Version 10 5 Example 2 Right click in the table or on the graph and select Restrict Calculation Range from the pop up menu Right click in the table for this pop up menu Or Select Restrict Calculation Range from either menu Right click in the graph for this pop up menu PSpice Advanced Analysis Users Guide 203 Chapter 6 Monte Carlo Product Version 10 5 Monte Carlo recalculates the statistics and only includes the restricted range of values Min cursor changed Restricted range is Max cursor to 9 cross hatched changed to 10 Cumulative Distribution Graph Runs 1 to 100 H FAAA H F3 FTPPTPRT i B E EA be SLL T IET T IETITET TTE H REND I i 1 H 4 H BA 85 A 38 7 88 289 e a ea p
98. ation engine that uses a slightly different algorithm than the LSQ engine which results in fewer PSpice Advanced Analysis Users Guide Product Version 10 5 measurement expression model Monte Carlo analysis N nominal value normal distribution function O optimization original value P parameter parameterized library Glossary runs to reach results and allows goal and constraint based optimization An expression that evaluates a characteristic of one or more waveforms A measurement expression contains a measurement definition and an output variable For example Max DB V load Users can create their own measurement expressions A mathematical characterization that emulates the behavior of a component A model may contain parameters so the component s behavior can be adjusted during optimization or other advanced analyses Calculations that estimate statistical circuit behavior and yield Uses parameter tolerance data Also referred to as yield analysis For a component parameter the nominal value is the original numerical value entered on the schematic For a measurement the nominal value is the value calculated using original component parameter values See Gaussian distribution function An iterative process used to get as close as possible to a desired goal See nominal value See component parameter A library that contains components whose behaviors can be adjusted with
99. ation for all device types supported by PSpiceAMS Only the information that is common across a set of devices is available in the template property file Model information contained in this file includes simulation information and smoke information The template property file contains definitions of simulation parameters It also lists the default values and the units for each of the simulation parameters For smoke it lists parameter definitions node to port mapping information and the list of the smoke tests to be performed for a particular device or a family of devices A template property file has the following sections m The model info section m The model params section mH The smoke section Q max ops desc Q pre smoke Q max ops Q smoke tests PSpice Advanced Analysis Users Guide 323 Chapter A Property Files Product Version 10 5 The template for the TEMPLATES PRP file is shown below won Creator Template property file created by analog uprev on Wed Jan 3 09 57 42 IST 2001 model info sas SMOKE pre_smoke sa max ops Cebus smoke_tests eee Cran Creator model info 4 34 model params level 0 IS wee SMOKE 324 PSpice Advanced Analysis Users Guide Product Version 10 5 Template property file Table A 1 lists the sections of property files and the analysis in which these sections are used Table A 1
100. ault values in the labeled text boxes PSpice Advanced Analysis Users Guide ey Chapter 9 Optimization Engines Optimization Run Controls 278 Product Version 10 5 4 Click OK Default LSQ Engine Options Value Sensitivity Perturbation Size 005 Absolute Function Convergence Tolerance 1 0e 20 Relative Function Convergence Tolerance 1 0e 10 X Convergence Tolerance 1 0e 4 False Convergence Tolerance 1 0e 14 Minimum Factor to Increment Trust Region 2 0 Maximum Factor to Increment Trust Region 4 0 Maximum number of trial runs 0 If the LSQ engine has problems finding a solution or stops too soon the convergence options can be modified to affect the algorithm Unlike PSpice where only one solution exists the LSQ engine potentially has many solutions minimums available in the design space Some of the available options are also in the PSpice options list although their effect in the LSQ optimization might not be as easy to follow as in PSpice The LSQ options affect how quickly a solution is obtained By tightening the options you may cause the LSQ engine to take extra iterations to find the solution By loosening the options you may find a less accurate solution One of the options available with the LSQ engine lets you limit the number of optimization trial runs The Max Number of Trial Runs option provides a way for you to stop the optimizer after a specified number of trial runs This option can be used in any o
101. aut Help 3 Click the browse icon 4 Browse and select your file PSpice Advanced Analysis Users Guide 153 Chapter 5 Smoke Product Version 10 5 The file name is added to the list in the Custom Derating Files text box and the drop down list Profile Settings Optimizer Monte Carlo Smoke Simulation Select the custom derating file in the drop down list after finding the file using the browse text box below Select derating type Create a list of custom derating files Type or browse to specify the full path of your custom file Files entered below will be added to the list of available derating types Custom Derating Files 1 x t Select the custom derating file from the drop down list Click OK 7 Click on the top toolbar to run a new Smoke analysis New results appear 8 Checkthe results To make changes follow the steps for changing derating options or schematic component values See Selecting standard derating on page 151 For power users Smoke parameters The following tables summarize smoke parameter names you will see in the Smoke results The tables are sorted by user interface parameter names and include m Passive component parameters 154 PSpice Advanced Analysis Users Guide Product Version 10 5 m Semiconductor component parameters m OpAmp component parameters For power users For passive components three names are used in Smoke
102. ax v onoise Click here to import a measurement created sithin PSpice Click to select the Hover your mouse Min means thatthe sensitivity The measurement data over a red flag to is very small but not zero measurement s set for review read the error worst case messages A zero 0 displays if there is minimum and no sensitivity at all maximum values Sorting data Double click on the Linear column header to sort the bar graph data in ascending order Double click again to sort the data in descending order PSpice Advanced Analysis Users Guide 59 Chapter 3 Sensitivity Product Version 10 5 Selecting the measurement to view Select a measurement in the Specifications table The data in the Parameters table relates to the measurement you selected Table Column heading Means Parameters Original The nominal component parameter values used to calculate nominal measurement Min The parameter value used to calculate the worst case minimum measurement Max The parameter value used to calculate the worst case maximum measurement absolute sensitivity The change in the measurement value divided by a unit of change in the parameter value relative sensitivity The percent of change in a measurement value based on a one percent change in the parameter value Specifications Original The nominal value of the measurement using original component parameter values Min The worst case minimum value for the me
103. be saved in the Advanced Analysis profile aap For power users Sensitivity calculations Absolute sensitivity Absolute sensitivity is the ratio of change in a measurement value to a one unit positive change in the parameter value For example There may be a 0 1V change in voltage for a 1 Ohm change in resistance The formula for absolute sensitivity is Ms Ma Phn Sy Tol Where M the measurement from the sensitivity run for that parameter Mn the measurement from the nominal run Tol relative tolerance of the parameter Py Nominal parameter value s Sensitivity Variation Default 40 By default the parameter value is varied within 40 of the set tolerance 66 PSpice Advanced Analysis Users Guide Product Version 10 5 Relative sensitivity Sensitivity procedure You can change this value to any desired percentage using the Profile settings dialog box 1 From the Edit drop down menu choose Profile Settings 2 Inthe Profile setting dialog box select the Sensitivity tab 3 Inthe Sensitivity Variation dialog box specify the value by which you want to vary the parameter value 4 Click OK to save your settings The values entered by you in the Profile Setting dialog box are stored for the future use as well Every time you load the project old values are used for advanced analysis simulations Example For example if you specify the Sensitivity Variation as 10 the paramet
104. c1 bias dat active EF i 0 x 3 File Edit View Simulation Trace Plot Tools Window Help E 8 x 5 66HZ 7 88Hz 988Hz P U UDUT DBCUCUOUT Frequenc D curvefit_testcases Min_Bp_doc bandpass schematic1 bias dat acti Freq 1 000E 03 1005 NENEEEEEEEN BAY Ai We will now optimize the values of the component parameters in the circuit such that the output waveform matches the waveform described in the reference file For this design example we will use reference txt for specifying the reference waveform for DB V Vout and P V Vout Note In a real life scenario you will have to create a reference file containing the reference waveform before you can use the curve fitting in Advanced Analysis Optimizer Opening Optimizer in Advanced Analysis From the PSpice menu choose Advanced Analysis Optimizer Selecting an engine 1 Click on the drop down list to the right of the Optimizer tool name 126 PSpice Advanced Analysis Users Guide Product Version 10 5 2 Example From the drop down list select the Modified LSQ engine Setting up component parameters 1 In the Parameters window add the parameters that you want to optimize to obtain the desired output Select the Click here to import a parameter from the design property file row In the Parameter Selection dialog box select C1 C2 C3 C4 R1 R2 R3 and R4 and click OK The selected components their original values and the min and max
105. ce optimizing run in either direction Note If you can t edit a value you might be viewing the historical data if y have already run an optimization Click here to Frrar Granh make changes which will affect the next run Run Number Controlling measurement specifications Cells with cross hatched backgrounds are read only and cannot be edited B To exclude a measurement from the next optimization run click the in the Specifications table which removes the check mark m To hide a measurements trace on the Error Graph click the graph symbol icon ja in the Specifications table which toggles the symbol off B To edit a measurement click on the measurement you want to edit then click on E PSpice Advanced Analysis Users Guide Product Version 10 5 Optimizer procedure overview BH To add anew measurement click on the row that reads Click here to import a measurement Note For instructions on setting up new measurements see Procedure for creating measurement expressions on page 240 B To export a new measurement to Optimizer or Monte Carlo select the measurement and right click on the row containing the text Click here to import a measurement created within PSpice Select Send To from the pop up menu The example for this topic comes with measurements already set up in PSpice Copying History to Next Run During optimization you might want to modify an Optimizer run by cop
106. chematic1 ac c Optimizer iteration 35 run 5 Temperature 27 0 Deg Simulation at 10 38 41 on 08 03 01 The simulator created 601 data points This trace is being displayed using 601 data points 302 PSpice Advanced Analysis Users Guide Product Version 10 5 Example Analyzing the trace data We know the bandwidth constraint failed We ll add a measurement in PSpice to find the 3dB point of the trace 1 Click at the bottom of the Measurements Results table The Evaluate Measurement dialog box appears Evaluate Measurement Simulation Output Variables Functions or Macros Measurements bd Bandwidth 1 db Bandwidth_Bandpass_3dB 1 Bandwidth_Bandpass_3dB_ gt Rangef1 CenterFrequency 1 db_level CenterFrequency_Range 1 db_level b Conversion ain 1 2 Conversion ain XR ange 1 2 begin x e Cutoff Highpass 3dB 1 Cutoff_Highpass_3dB_ Range 1 begin Cutoff Lowpass 3dB 1 Cutoff_Lowpass_3dB_Range 1 begin DutyCycle 1 DutyCycle XRange 1 begin x end x Falltime NoO vershoot 1 Falltime StepResponse 1 Fallime StepResponse XRange 1 beg GainMargin 1 2 Max 1 Max XRange 1 begin x end x Min 1 Min Range 1 begin x end x NthPeak 1 n occur ETE wf Trace Expression mas db V Load 3 Cancel Help 2 Inthe Trace Expression field at the bottom type in max db v load 3 4 v Analog Digital IV Voltages v Currents IV Power IV Noise Hz2 IV Alias Names v S
107. cification s most sensitive components Run a sensitivity analysis to find them m Use good engineering judgment Don t vary components whose values need to stay the same for successful circuit operation For example if the input and output resistors need to be 50 ohms for impedance matching do not choose those components to optimize m Vary just one component if varying other components can cause the same effect For example in an RC filter combination both the resistor and capacitor affect the bandwidth Selecting one parameter simplifies the problem If your goal cannot be met with one parameter you can add the second parameter Guidelines for setting up Parameters m Make sure that ranges you specify take into account power dissipation and component cost For example a resistor with a small value low ohms could require a larger more expensive power rating W Start with a small set of parameters three or four and add to the list during your optimization process especially when running the LSQ engine 86 PSpice Advanced Analysis Users Guide Product Version 10 5 Setting up specifications Optimizer procedure overview Aim for parameters with initial values near the range midpoints Optimizer has more trouble finding solutions if parameter values are close to the endpoint of the ranges Keep optimization parameter ranges within 1 or 2 orders of magnitude Using the Advanced Analysis Optimizer you can set
108. come Advanced Analysis allows PSpice and PSpice A D users to optimize performance and improve quality of designs before committing them to hardware Advanced Analysis four important capabilities sensitivity analysis optimization yield analysis Monte Carlo and stress analysis Smoke address design complexity as well as price performance and quality requirements of circuit design Advanced Analysis is integrated with OrCAD Capture and is available on Windows 98 Windows NT and Windows 2000 platforms PSpice Advanced Analysis Users Guide 9 Chapter Before you begin Product Version 10 5 How to use this guide This guide is designed to make the most of the advantages of onscreen books The table of contents index and cross references provide instant links to the information you need Just click on the text and jump Each chapter about an Advanced Analysis tool is self contained The chapters are organized into these sections m Overview introduces you to the tool m Strategy gives you tips on planning your project B Procedure lists each step you need to successfully apply the tool m Example lists the same steps with an illustrating example m For power users provides background information If you find printed paper helpful print only the section you need at the time When you want an in depth tutorial print the example When you want a quick reminder of a procedure print the procedure Symbols and conve
109. contain smoke parameters Use the online PSpice library list to identify components in the standard PSpice libraries that have smoke parameters See also Smoke parameters on page 154 For example in Capture s property editor a resistor could provide the following smoke parameter information Property Value POWER RMAX MAX TEM RTMAX P Use the design variables table to set the values of RMAX and RTMAX to 0 25 Watts and 200 degrees Centigrade respectively See Using the design variables table on page 33 Location of Advanced Analysis libraries The program installs the Advanced Analysis libraries to the following locations Capture symbol libraries Target directory XCaptureW ibrary PSpiceVAdvAnlsV PSpice Advanced Analysis model libraries Target directory PSpice Library Using Advanced Analysis libraries In Capture there are three ways to quickly identify if a component is from an Advanced Analysis library PSpice Advanced Analysis Users Guide 27 Chapter 2 Libraries Product Version 10 5 B Looking in the online Advanced Analysis library list m Using the library tool tip in the Place Part dialog box m Using the Parameterized Part icon in the Place Part dialog box Using the online Advanced Analysis library list 28 You can find the online Advanced Analysis library list from your Windows Start menu 1 Doone of the following Q From the Windows Start menu choose the OrCAD 10 0 prog
110. ct from the drop down list of discrete values tables 3 Select the 1096 discrete values table for resistor R8 Repeat these steps to select the same table for resistors R6 and R4 Parameters Hext Run LM Parameter Discrete Table Resistor 2 1096 C vug Resistor 2 10 2 10 Eo o VALUE Resistor B 1096 Click here to import a parameter from the PSpice Advanced Analysis Users Guide Product Version 10 5 Example 4 Click p gt Discrete c Click The Discrete engine runs First the Discrete engine finds the nearest commercially available component Next the engine reruns the simulation with the new parameter values and displays the measurement results At completion the Current column in the Parameters table is filled with the new values i SCHEMATIC PSpice Advanced Analysis Optimizer M iri Current values File Edit View Run Analysis Window Help 181 xj that are je S x Boe fori zw Cd hm RAAF commercially available Error Graph Parameters Hext Run using discrete TIE LI E N re E ESA VALUE Resistor 10 i values tables 1 2 3 25 in lis dil VALUE Resistor 10 Click here to import a parameter from the design propert Raa Namber Specifications Next Run Profile Measurement Min Max Original Current Error ac sim max db v load 5 5 5000 H i H ac sim bandwidth v load 3 200000000 ac sim min l
111. d then click the mouse in a new location on the x axis The cursor s location changes and the max value and yield numbers are updated in the Statistical Information table Note Moving the cursor does not update the rest of the statistical results for this new min max range Use Restrict Calculation Range to recalculate the rest of 200 PSpice Advanced Analysis Users Guide Product Version 10 5 Example the statistical results for this min max range Reviewing the CDF graph The CDF graph is a cumulative stair step plot 1 Select the Max DB V Load measurement in the Statistical Information table 2 Rightclickon the PDF graph and select CDF Graph from the pop up menu Cumulative Density Graph Runs 1 to 100 Mink 84 85 86 87 88 89 9 91 92 93 94 95 96 97 98 99 10 101 102 103 104 105 104 10 7 108 Max DB V Load Number of Runs CDF graph with max cursor selected before cursor is moved for restricted range calculation 3 Right click on the graph and select Zoom In to view a specific range 4 Click the Max cursor to select the cursor The Max cursor turns red 5 Click the mouse at 10 on the x axis The cursor moves to the new position on the x axis 6 Click the Min cursor and click the mouse at 9 on the x axis PSpice Advanced Analysis Users Guide 201 Chapter 6 Monte Carlo Product Version 10 5 When you change the cursor location the min max and yield values are updated on the Statistical Inform
112. d with a user defined range Forward is the default direction start_point The starting point to begin a search The current point is the default Use this To start the search at this A the first point in the search range Begin the first point in the search range the last point in the search range End the last point in the search range xn a marked point number or an expression of marked points for example x1 x1 x2 x1 2 consecutive points Defines the number of consecutive points required for a condition to be met Usage varies for individual conditions the default is 1 A peak is a data point with one neighboring data point on both sides that has a lower Y value than the data point If consecutive_points is 2 and lt condition gt is PEak then the peak searched for is a PSpice Advanced Analysis Users Guide 261 Chapter 8 262 Measurement Expressions Product Version 10 5 data point with two neighboring data points on both sides with lower Y values than the marked data point range x range y Specifies the range of values to confine the search The range can be specified as floating point values as a percent of the full range as marked points or as an expression of marked points The default range is all points available Examples This range Means this 1n 200n X range limited from 1e 9 to 200e 9 Y range defaults to full range 1 5 20e 9 0 1m both
113. dditional feature called Advanced Analysis Using Advanced Analysis you can run the following analyses BH Sensitivity m Monte Carlo B Optimizer NH Smoke B Parametric Plotter For Advanced Analysis runs along with the simulation data Advanced Analysis needs other device specific data as well Device specific data such as device parameter tolerance and maximum operating conditions is available in property files These property files are shipped along with PSpice libraries Property files are organized as the template property file and the device property file The template property file contains generic information for a particular class of devices The device property file contains information specific to a device The diagram shown below depicts the Capture PSpice flow and the files used in the flow PSpice Advanced Analysis Users Guide 321 Chapter A Property Files Creating Schematic Generating Netlist Simulating the design 322 Used for Lised for Used far Used for Symbol Information Netlist Information Simulation Models Device Infarmation Provides Provides Product Version 10 5 olt file a a Property files and The implement property Jib file Property files template prp and device prp PSpice Advanced Analysis Users Guide Product Version 10 5 Template property file Template property file The template property file TEMPLATES PRP contains inform
114. de Product Version 10 5 Example Setting Monte Carlo options 1 From the Advanced Analysis Edit menu select Profile Settings click the Monte Carlo tab and enter the values shown in the dialog box Undo Redo Select Profile Y Cut ze Settings from the Edit menu to bring up Monte Carlo options Click to select Monte Carlo settings Set Number 9 Runs to 100 2 Click OK PSpice Advanced Analysis Users Guide 195 Chapter 6 Monte Carlo Product Version 10 5 Running Monte Carlo Starting the analysis 1 Click b Select Monte Carlo from P d drop down list Il Monte Carlo p Click to start a Monte Carlo P analysis The Monte Carlo analysis begins The messages in the output window give you the status Monte Carlo calculates a nominal value for each measurement using the original parameter values After the nominal runs Monte Carlo randomly calculates the value of each variable parameter based on its tolerance and a flat uniform distribution function For each profile Monte Carlo uses the calculated parameter values evaluates the measurements and saves the measurement values Monte Carlo repeats the above calculations for the specified number of runs then calculates and displays statistical data for each measurement 196 PSpice Advanced Analysis Users Guide Product Version 10 5 Example Ten bins of measurement data are displayed on the graph From the View menu select
115. del shipped with PSpiceAMS Parts created using the Model Editor do not have the awb prefix Within a model definition you have the following sections B device info m device max ops BH model params The device info section 334 This section lists the MODEL TYPE SYMBOL NAME and PORT ORDER The first line in the device info section specifies MODEL TYPE The syntax is MODEL TYPE Numeric value For example MODEL TYPE 706 MODEL TYPE refers to the model template number in the template property file The line SYMBOL NAME 7 Pin Opamp refers to the name of the schematic symbol The line is used by the Model Editor during PSpice Advanced Analysis Users Guide Product Version 10 5 The device property file part creation In the above example the schematic symbol created by the Model Editor will have 7_Pin_Opamp as the symbol name Finally PORT_ORDER lists the pin names in the order of the interface nodes on the SUBCKT statement in the PSpice model The PORT_ORDER information is available only for template based PSpice models and is used during netlist creation The model_params section of a device property file lists the default value of the simulation parameter the default positive and negative tolerance values and the default distribution type By default the distribution type is flat for all parameters The distribution type is used during the Monte Carlo analysis Note To
116. dings in the reference file If you open the reference file reference txt you will see that PHASE is the heading of the second column and the third column has no heading When the column headers are blank in the reference file the reference waveform drop down list displays entries such as Column 2 and Column 3 instead of a name Specify the tolerance and weight at 5 and 1 respectively This completes the process of creating a new curve fit specification In case you want to enable dynamic viewing of the output waveform select the third field in the On Off column Similarly add another specification Specify the trace expression as DB V out reference file as reference txt reference waveform as Column 2 tolerance as 3 and weight as 1 Turn the dynamic viewing on PSpice Advanced Analysis Users Guide Product Version 10 5 Example The snapshot of the Optimizer after you have modified the settings is shown below i SCHEMATIC PSpice Advanced Analysis Optimizer File Edit Yiew Run Analysis Window Help 81 xl smsa sre ome sa a nm a am Fe Parameters Hext Run Parameter Original Diege jv Tete vae ete vae L v g 9 jv ie Deke jvue Error Graph o E 3 wW Run Number LJstandart ZZ Curve Fit Curve Fit Hext Run zl On Off Profile Trace Expression Reference File Ref Waveform Tolerance Weight E
117. directory gt PSpice Tutorial Sy Local Disk C Cadence PSD_ 14 1 PS pice Tutorial Troubles hooting Capture 2 From your schematic editor open the rfampt project from the rfampt folder PSpice Advanced Analysis Users Guide 297 Chapter 10 Troubleshooting Product Version 10 5 3 Open the schematic page RF Amplifier THE D1 Smoke Limit RME 0 25 RS 0 005 RTMAX 200 Tok races hulk 12 CTOL 10 CMAX 5D RTOL 10 CBMAX 125 LTOL 0 CSMAN 0 005 VTOL 0 CTMAX 125 IT L 0 CIMAX 1 g LMA 5 User varbkz OSMAXx 300 Inte 1 In R5 i ccMEMDEEE 50 ACC j In j HE Toup pm TRAN Sing Sm Wen AG 1 i pc n 4 With the SCHEMATIC1 AC simulation profile selected click to run the simulation 5 From PSpice menu in Capture select Advanced Analysis Optimizer Advanced Analysis opens to the Optimizer view 298 PSpice Advanced Analysis Users Guide Product Version 10 5 Example There are four measurement goals included in this example Specifications Next Run On Off Profile Measurement Min Max types Weight Loo E ES tsm schematict vextb amp vLoso s5 20 EE e eee oe 4 lE rt_amp schematict Min 10 Log1 O v inoise Constraint 1 Pe TEE LES Ir amo schematit Maxcvoncise am 6 If there is any history in the Error Graph right click in the error graph window and select Clear History from the pop up menu c CAS SIU NN Error Graph
118. dvanced Analysis click on the row containing the text Click here to import The Parameters Selection dialog box appears 2 Highlight the components you want to vary and click OK The components are now listed in the Parameters table Sensitivity 1 After you run the sensitivity analysis select the most sensitive components and right click 2 Fromthe pop up menu select Send to Optimizer Selected components are listed in the Parameters table When you add a component to the Parameters table the parameter name the original value of the parameter and the minimum and maximum values of the parameter are also listed in the Parameters table The Min and Max values sets the range the engine will vary the components parameters These values are calculated by the Optimizer based on the original value By default Min value is one tenth of the Original value and Max value is ten times the Original value You can use your engineering judgment to edit the Parameters table Min and Max values for the Optimization PSpice Advanced Analysis Users Guide 85 Chapter 4 Optimizer Product Version 10 5 caution If you reimport any of the parameter that is already present in the Parameters table the entries in the Original Min and Max columns are overwritten by the new values Guidelines for selecting components Optimization parameters need to carefully selected to ensure quicker optimizations and the best results M Vary your spe
119. dvanced Analysis library For each parameterized component in your design set the parameter value individually on the component using your schematic editor A convenient way to add parameter values on a global basis is to use the design variable table See Using the design variables table on page 33 Note If you set a value for POSTOL and leave the value for NEGTOL blank Advanced Analysis will automatically setthe value of NEGTOL equal to the value of POSTOL and perform the analysis PSpice Advanced Analysis Users Guide 31 Chapter 2 Libraries Product Version 10 5 Note Asa minimum you must set a value for POSTOL If you set a value for NEGTOL and leave the POSTOL value blank Advanced Analysis will not include the parameter in Sensitivity or Monte Carlo analyses Adding additional parameters 32 If the component does not have Advanced Analysis parameters visible on the symbol add the appropriate Advanced Analysis parameters using your schematic editor For example For RLC components the parameters required for Advanced Analysis Sensitivity and Monte Carlo are listed below The values shown are those that can be set using the design variables table See Using the design variables table on page 33 Part Tolerance Property Name Value Resistor POSTOL RTOL Resistor NEGTOL RTOL Inductor POSTOL LTOL Inductor NEGTOL LTOL Capacitor POSTOL CTOL Capacitor NEGTOL CTOL For RLC components the parameter requ
120. e 9 40 295 E 9 7 Se S S E a a a Ys Ea e 10 5 MOOK IIe Max DB v Load 10096 50 Percent of Runs 0 E Statistics E Raw Meas Profile Measurement rf_amp schematict Max DB v Load 9 4268 280 0109m 9 0021 10 0017 Editing the Cursor Min Note the new results a and Max cells also statistics based on the changes the range restricted range Raw Measurements Table This read only table has a one to one relationship with the Statistical Information Table For every row on this table there is a corresponding row on the other table where the statistics are displayed 1 Click the Raw Meas tab The Raw Measurements table appears 2 Select the Max DB V load measurement row and double click the far left row header The row run data is sorted in ascending order Note If you want to use the data in an external program 204 PSpice Advanced Analysis Users Guide Product Version 10 5 Example you can copy and paste a row of data Double click on a row header Click on the Raw Meas Run 81 has the lowest to sort run data tab to select measurement value Ele Elec Profile B Monte Larlo All mogte carlo run 99 completed OS For Help press F1 me oer ra WR 4 Scroll to see all run values Data rows can be copied and pasted to external programs Controlling Monte Car
121. e ADL tte o TASSE eit ire bert camion E 221 A alyzing RESUNS 3 15 25 059 52 511 10 PE oboe DE ERR DAE Re bat aa ee nee oe 222 Plot Information tab 250229900 01 5 hides Cid po Fen ace dS Bap sdb d Jut abd xs etek Sd xiu ed 223 July 2005 6 Product Version 10 5 PSpice Advanced Analysis Users Guide Adding DIOL estas se agen e setae Malen tud n a se ae oy Sey and t tuc lle ei E E Rea edad 223 Viewing the plot ul zoo torpe usd c cune va ra a Qo OR RR te tc cd a ar ER V TOR EN 225 MedSHtetiete Tab 3553 4 vec reise dal Aog co a sr en ete eui af a ai eap Ses RO AE A 225 Examples syss ei Geha Mic Mow uina nitro e alte Mea Me tuf S pta oL Mar io ote ru fy 225 8 Measurement Expressions uuuLutuuuuuuuusuuussusuuu 239 Intl etldpleL ure fce xoi bolt oed porno Red eee eats eae sos eae Gales ob iv d 239 Measuremehts OVERVIEW rpari xa QE X EXER IR EE ARE rd pat EUR ERE Bae 239 Measurermeritslraledy e dona at ater d ee de UR e xaxa E vetu x bods RE dd 240 Procedure for creating measurement expressions 0 0 eee 240 jo TERRE Y 240 Composing a measurement expression ccc eens 241 Viewing the results of measurement evaluations llus 242 EXAMP x42 dum Sea Cee Deren iut FO a SEE gt ee Gud duds 098 QU TARTE JO Pn UD EG 242 Viewing the results of measurement evaluations lllllllsu 246 Measurement definitions included in PSpice 00 0
122. e S se Be lex Smoke Right click on Q1 and from the pop up menu select Find in Design This takes you to the schematic where the component parameter can be changed 4 Resolve the component stress a Right click on Q1 VCE and from the pop up menu select Find in Design to go to the schematic and adjust Q1 s VCE value a Right click and from the pop up menu select Deratings No Derating to change the derating option back to No Derating 5 Click I onthe top toolbar to rerun Smoke analysis after making any adjustments 6 Check the results 152 PSpice Advanced Analysis Users Guide Product Version 10 5 Example Selecting custom derating If you have your own custom derating factors you can browse to your own file and select it for use in Smoke For information on creating a custom derating file see our technical note posted on our web site at www orcadpcb com 1 Once you have your custom derating file in place right click and from the pop up menu select Derating 2 Select Custom Derating Files from the pull right menu I nl a oic iie Optimizer Monte Carlo Smoke Simulation 9 Smoke tab Select derating type Click to hs browse to SETET MEM q your Cu stom derating file Create a list of custom derating files Type or browse to specify the full path of your custom file Files enterez will be added to the list of available derating vr z axles Cancel Set Def
123. e sensitivity analysis Sensitivity runs We can see that in the relative sensitivity analysis Capacitors 3 6 and 7 are not critical to the bandwidth response 306 PSpice Advanced Analysis Users Guide Product Version 10 5 Optimizer rerun Example We ll return to Optimizer and remove the capacitors from the optimization analysis Reducing variables may help Optimizer reach a solution 1 Return to the Optimizer tool and in the Parameters table hold down your shift key and select the capacitor rows 2 Right click and select Delete from the pop up menu Parameters Hext Run On Off Component Parameter E vj d e fe vae 3j 35000 Ee fre jvaue 235 705 E ES VALUE 235 o TOS 4 n gt C Import Parameters Find in Design mport a parameter from the design pro Import PSpice Optimizer Data amp Cut Copy Measur m 5 Constraint d within PSnice 3 If there is any history in the Error Graph right click in the Error Graph window and select Clear History from the pop up menu 4 Select the Modified LSQ engine and click on the top toolbar to start the optimization The optimization starts and finds a solution PSpice Advanced Analysis Users Guide 307 Chapter 10 Troubleshooting Common problems and solutions Analysis fails Problem Analysis fails Product Version 10 5 This section suggests solutions to problems yo
124. e the expression Rival R2val Table 4 1 Valid Operators and Functions for Advanced Analysis Optimizer Expressions Operator Meaning addition E subtraction PSpice Advanced Analysis Users Guide Product Version 10 5 Terms you need to understand Derivative Simulation profile Advanced Analysis Profile PSpice Advanced Analysis Users Guide Table 4 1 Valid Operators and Functions for Advanced Analysis Optimizer Expressions continued Operator Meaning multiplication division id exponentiation exp ex log In x log10 log40 X sin sine COS cosine tan tangent atan arctangent Note Unlike trace functions and goal functions Optimizer expressions are evaluated without using a simulation A derivative can be defined as the rate of change of specification value with the change in parameter value A simulation profile is used in the basic simulation flow A simulation profile contains and saves the simulation settings for an analysis type so that it can be reused An advanced analysis profile contains and saves the advanced analyses optimizer sensitivity settings so it can be reused 79 Chapter 4 Optimizer Optimizer procedure overview Workflow Schematic editor PSpice Set up or edit circuit Create measurements Check waveforms and measurement results Change components or edit parameter values These processes are explained in your schematic editor and PSpice u
125. e the three columns on the right in the list The abbreviations in the parameter columns have the following meanings Means the component Has tolerance parameters in the model Does not have tolerance parameters in the model Has optimizable parameters in the model Does not have optimizable parameters in the model Has smoke parameters in the model Does not have smoke parameters in the model Has a distribution parameter associated with the model Does not have a distribution parameter associated with the model Using the library tool tip PSpice Advanced Analysis Users Guide One easy way to identify if a component comes from an Advanced Analysis library is to use the tool tip in the Place Part dialog box 1 From the Place menu select Part 29 Chapter 2 Libraries Product Version 10 5 The Place Part dialog box appears Enter a component name in the Part text box Hover your mouse over the highlighted component name A library path name appears in a tool tip Check for ADVANLS in the path name If ADVANLS is in the path name the component comes from an Advanced Analysis library Using Parameterized Part icon Another easy way to identify if a component comes from an Advanced Analysis library is to use the Parameterized Part icon in the Place Part dialog box 1 From the Place menu select Part The Place Part dialog box appears Enter a component name in the Part text box Or Scroll through the Par
126. e tutorial Capture pspiceaa rfamp 2 Open the RFAmp project The RF amplifier circuit example Assign global tolerances RF Amplifier PYES using this table pi Tok raices CTOL 10 RTOL 10 LTOL 0 VTOL 0 ITOL 0 User Varbbks TE Sing 5m Wen wo 3 70 3 Selectthe SCHEMATIC1 AC simulation profile 108 PSpice Advanced Analysis Users Guide Product Version 10 5 Example The AC simulation included in the RFAmp example Simulation Settings AC x General Analysis Configuration Files Options Data Collection Probe window Analysis type AC Sweep Type _ C Linear Start Frequency fik Options Logarithmic End Frequency I G Decade Points Decade fio Monte Carlo Worst Case Parametric Sweep r Noise Analysis Temperature Sweep Save Bias Point Iv Enabled Dutput Voltage viLoad Load Bias Point IA Source M Interval Output File Options Include detailed bias point information for nonlinear controlled sources and semiconductors OP Cancel Apply Help 4 Click to run the PSpice simulation 5 Review the results tf_amp SCHEMATIC1 ac dat active 5 8nU4 u onoise 18KHZz I ra 1 8HHz 18HHz 188HHz 1 8GHZ Noise Figure Frequency The waveforms in PSpice are what we expected Measurement Results Evaluate Measurement In PS pice view max db v load bandwidth v load 3 m eas u re m e niresu
127. e wrong profile for the type of measurement you re evaluating PSpice Advanced Analysis Users Guide From the Simulation menu in PSpice choose Edit Profile to open the Simulation Settings dialog box Ensure that the data save start time in the Analysis tab is 0 Smoke analysis works only if data save start time is zero seconds Or From the Simulation menu in PSpice choose Edit Profile to open the Simulation Settings dialog box Ensure that the data collection options in the Data Collection tab is set to All for voltages currents and power Decrease the number of runs in the Monte Carlo settings tab from the Edit menu select Profile Settings and click the Monte Carlo tab Check the selected profile and change it to the profile that applies to your measurement For example change to an AC profile to evaluate bandwidth 309 Chapter 10 Troubleshooting Problem Analysis fails Possible cause Product Version 10 5 Solution Optimization didn t converge Optimization didn t converge after running through several iterations Optimization didn t converge but it looked like it was improving 310 The engine may have found a local minimum which may not be the best solution See Local and global minimums on page 270 The parameters have changed the circuit s behavior so the simulation results may not provide the information needed to meet the measurement goal Too few iterations
128. eC A LEE oN oe e AL E MM 47 Controlling Sensitivity 553 55 hors 4240 tat hee t pani esaet wr das 50 Sending parameters to Optimizer l l 52 Sensitivity calculations 6a ese REUS pie oov ERE Cee We oae d ag ig sober oen 66 4 OPUNE e TS TNT 71 Its SOMATIC sepe aedis uat I Rab alee aoa abel Roo oc ag Dog SU CAT UA aba d un x bee p ER E 71 Optimizer overvieW xu ne xci Aer Rap Kee o det idee gend fau ARA RA VAM dea De do dina e 71 Terms you need to understand sso et ERR E PEEE DR ERR 73 Optimizer procedure overview 1 323 25 sor hA Sa ea Rd REESE IS 80 Setting up in the circuit in the schematic editor llssss 82 Setting up Optimizer in Advanced Analysis llllllsss 83 Et nnimad Optimizer g oodd ra teme aha ORE QU LADEN Brenta REIR SUE Eu 99 Assigning available values with the Discrete engine 0000005 105 Finding components in your schematic editor eee 106 Examining a Run in PSpice 394 stots Sit edil dodi hohe DE i cM rM e E Ed 106 July 2005 4 Product Version 10 5 PSpice Advanced Analysis Users Guide Example 26 70id slits doh E CIT OT TUTTI LR 107 Optimizing a design using measurement specifications 107 Optimizing a design using curve fit specifications 0 0 125 For Power USERS 2 co vue pos Ote BANS oar han e tran e a Ae ER e A tot take othe t 131 What ar
129. eDiscrete Tables o v E b EE IER SEX TCR D Da ROR Re 131 Adding User Defined Discrete Table ccc eee 132 Device Level Parameters 15i sexum oa ae ce RO SERE Ce qn ae a 133 Optimizerdo9 Mes ress pesci ud averacert ut quo det RR Ea tos Ia icit se rd AE EN E aa 135 Engine OVervIBW dachte d eod QU dA n UR P arene ava P ER OE RIA Thelen ca QE P Df a 135 5 SMOKE uscire LoDRA united cii eM et dE eed Sette o A see idm 137 Itisthis chaptel gt 2x seat beste te teas teste oe heehee ee Sie e eh ee ees 137 SIHOKE OVOIVIGW ss 2 etir aea Da 7042 miha Bona pu dota 2 6 Row oni Govan geste dor elton aoe bo de 137 SMOK strategy sed alae ales ep a a E a e a T e ge ee E aw aE 138 Pl nahead oae eek n a E A EE AETA Dc E ace CR DU dice eared E RES 138 WOTKIHOW moneri et Ene Pa sels E oma E A a too Eee d a aded 139 SITIOKG DEOCOSUEO saner Dc odana E ec Rr E O nr a A EE EEE E E arva ere Eels 139 Setting up the circuit in the schematic editor nunaa annae 139 AUMRING SMOKE a 2b metet s ERRARE REOR DC B qim pide ides ds 140 Configuring Smoke 11 2 294 anaana we Fonsi dioe Ionas DOR Ip dice ald o dur e oen nn 142 Example x eL asa at dead oe odo tds eee mae Rae dolar dt are sae G9 d RO CE YO Doi nd 144 COGEVIOW Sire sse edil Eo nex WEE Papa afa b E EA e dea qe rude dem dre 144 Setting up the circuit in the schematic editor lllsss 144 R ning Smoke aye votre otha nd ita ke e sete t ob ME Ga PU A RA
130. ecification simultaneously This is the trade off Click once on the cursor Click in your desired location The cursor moves to the location of the second click Not enough disk space or memory Problem Not enough disk space or memory Return to top of table Possible cause Solution get a disk space error message or an out of memory message and I m running a Monte Carlo analysis 318 Too much data is being saved for the Monte Carlo runs For example in a 10 000 run Monte Carlo analysis where all data is collected and saved the data file and memory usage may become very large Turn off the option to save all simulation waveform data in Advanced Analysis By doing this saved data will be limited to just the current run However at this setting the simulation will run slower To turn off the data storage 1 From the Advance Analysis menu select Edit Profile Settings Simulation tab 2 From the Monte Carlo field select Save None from the drop down list Advanced Analysis will overwrite the data file for each run PSpice Advanced Analysis Users Guide Product Version 10 5 Problem Not enough disk space or memory Possible cause Common problems and solutions Solution get a disk space error message or an out of memory message and I m running a Monte Carlo analysis continued Too much data is being collected for each simulation run For instance collecting
131. ed Analysis Users Guide 159 Chapter 5 Smoke Product Version 10 5 Smoke Parameter Op Amp Name Component Maximum Operating Condition VMMAX OpAmp Maximum input voltage inverting VMMIN OpAmp Minimum input voltage inverting Adding Custom Derate file Why use derating factors If you want a margin of safety in your design apply a derating factor to your maximum operating conditions MOCs If a manufacturer lists 5W as the maximum operating condition for a resistor you can insert a margin of safety in your design if you lower that value to 4 5W and run your simulation with 4 5W as the safe operating limit SOL As an equation MOC x derating factor SOL In the example 5w x 0 9 4 5w the derating factor is 0 9 Also 4 5W is 90 of 5W so the derating factor is 90 A derating factor can be expressed as a percent or a decimal fraction depending on how it s used in calculations What is a custom derate file 160 A custom derating file is an ASCII text file with a drt extension that contains smoke parameters and derating factors specific to your project If the no derating and standard derating factors provided with Advanced Analysis do not have the values you need for your project you can create a custom derating file and type in the specific derating factors that meet your design specifications Figure 2 shows a portion of a custom derating file The file lists resistor smoke parameters and derating f
132. eform BH One or more search commands These commands specify how to search for the interesting points 1 Decide what you want to measure PSpice Advanced Analysis Users Guide 253 Chapter 8 Measurement Expressions 5 Product Version 10 5 Examine the waveforms you have and choose which points on the waveform are needed to calculate the measured value Compose the search commands to find and mark the desired points Use the marked points in the Marked Point Expressions to calculate the final value for the waveform Test the search commands and measurements Note An easy way to create a new definition From the PSpice Trace menu select Measurements to open the Measurements dialog box then Q Select the definition most similar to your needs Q Click Copy and follow the prompts to rename and edit Writing a new measurement definition 254 1 From the PSpice Trace menu choose Measurements The Measurements dialog box appears Click New The New Measurement dialog box appears Type a name for the new measurement in the New Measurement name field Make sure local file is selected This stores the new measurement in a prb file local to the design Click OK The Edit New Measurement dialog box appears Type in the marked expression Type in any comments you want Type in the search function PSpice Advanced Analysis Users Guide Product Version 10 5 For power users Note For syntax inf
133. el 2 are used while simulating the device Note For some of the models the simulation parameters PSpice Advanced Analysis Users Guide Product Version 10 5 Template property file are divided into different levels The level of parameters determines the complexity of the model Higher the level more complex is the model Level 1 indicates the lowest level of complexity While simulating a device you can specify the level of the simulation parameters to be used by adding the LEVEL property on the symbol in the schematic editor Use Level 1 simulation parameters when you want to fast but not so accurate simulation results Using Level 3 parameters increases the accuracy of simulation results but also increases the simulation time Template based OPAMP models are an example of multi level models supported by PSpiceAMS A part of the TEMPLATES PRP file containing the model params section for an OPAMP model is shown below model params level 1 VOS n description Offset voltage units my val le 6 level 2 CMRR description Common mode reject units V V val 100000 Within the LEVEL section various simulation parameters are defined A parameter definition includes parameter description measurement unit and the default parameter value The information listed under the model_params section is used by the Model Editor also The Model Editor reads this informati
134. el parameters to a set of measurements or when minimizing more than one goal Note All four cases allow simple bound constraints that is lower and upper bounds on all of the parameters PSpice Advanced Analysis Users Guide 73 Chapter 4 Optimizer Curve fitting Parameter Specification 74 Product Version 10 5 Optimizer also handles nonlinear function as constraints Curve fitting is a method of optimizing a model to a waveform In this method the specifications are represented using a collection of x y points These points describe the response of a system or a part of it A parameter defines a property of the design for which the Optimizer attempts to determine the best value within specified limits A parameter can m Represent component values such as resistance R for a resistor m Represent other component property values such as slider settings in a potentiometer W Participate in expressions used to define component values or other component property values m Be a model parameter such as IS for a diode Example A potentiometer part in a schematic uses the SET property to represent the slider position You can assign a parameterized expression to this property to represent variable slider positions between 1 and O During optimization the Optimizer varies the parameterized value of the SET property A specification describes the desired behavior of a design in terms of goals and constraint
135. ement goal Too few iterations Use the Random engine to search for alternate starting points Go to the Error Graph history and copy the best Random engine result to the Nth run the end Then switch to the Modified LSQ or LSQ engine to pinpoint the final answer Use the Troubleshoot in PSpice feature to check the shapes of the traces and make sure they are appropriate for the desired measurement right click on a measurement row and select the Troubleshoot command from the pop up menu For example do the traces show that the filter still looks like a bandpass Try changing the simulation settings to increase the range of frequencies Or Restrict the parameter ranges in the Optimizer Parameters table to prevent the problem Increase number of iterations in the Optimizer engine settings tab from the Edit menu select Profile Settings and click the Optimizer tab PSpice Advanced Analysis Users Guide Product Version 10 5 Problem Analysis fails Possible cause Common problems and solutions Solution Optimization didn t converge Selected parameters may not Parameters didn t change be sensitive to the chosen much from their original measurement values Optimization didn t converge One or more parameters may It was improving for a few have reached its limit iterations then the Error Graph traces flattened out Choose different parameters more sensitive to the chosen measurement
136. ements Results table check the measurement syntax and the variables used a In PSpice click 24 to edit the simulation profile Q Inthe schematic editor make changes to parameter values Rerun the simulation in the schematic editor Return to Advanced Analysis 7 If you made changes PSpice Advanced Analysis Users Guide 295 Chapter 10 Troubleshooting Product Version 10 5 a Toameasurement in PSpice copy the edited measurement from PSpice to the Advanced Analysis Specifications table Use Windows copy and paste Q Toparameter values in your schematic editor import the new parameter data by clicking on the Optimizer Parameters table row titled Click here to import a parameter 8 Right click in the Error Graph and from the pop up menu select Clear History 9 Rerun Optimizer Example To show how to use the troubleshooting feature we need an optimization project that fails to find a solution We ll use the example in the Troubleshoot folder from the Tutorial directory This example results in an unresolved optimization Strategy In this example we ll B Open the RF amp circuit in the Troubleshooting directory m Run the AC simulation and open Optimizer m Use the troubleshoot function to view waveforms of the problem measurement Setting up the example 1 In your schematic editor browse to the TroubleShoot directory 296 PSpice Advanced Analysis Users Guide Product Version 10 5 Example lt target
137. ent values based on the Monte Carlo runs Right click the graph to select zoom setting another graph type and y axis units A pop up menu appears Q Select Zoom In to focus on a small range of values Q Select CDF Graph to toggle from the default PDF graph to the CDF graph Q Select Percent Y axis to toggle from the default absolute y axis Number of Runs to Percent of Runs To change the number of bins on the x axis From the Edit menu select Profile Settings click the Monte Carlo tab and typing a new number in the Number of Bins text box If you want more bars on the graph specify more bins up to a maximum of the total number of runs Higher bin numbers show more detail but require more runs to be useful The CDF graph is another way to display a probability distribution In mathematical terms the CDF is the integral of the PDF 1 Select a measurement row in the Statistical Information table If the CDF graph is not already displayed right click on the PDF graph and select CDF Graph from the pop up menu The statistical display for the cumulative distribution function is shown on the CDF graph PSpice Advanced Analysis Users Guide Product Version 10 5 Monte Carlo procedure Right click the graph to select zoom setting and y axis units A pop up menu will appear Q Select Zoom In to focus on a small range of values Q Select PDF Graph to toggle from the current CDF graph to the default PDF gra
138. ents for Measurement Evaluation Mat 00s Note You will only be using the Simulation Output Variables list on the left side Ignore the Functions or Macros list Traces for Measurement Arguments AE Digital 244 PSpice Advanced Analysis Users Guide Product Version 10 5 Example 6 Uncheck the output types you don t need if you want to simplify the list Analog Operators and Functions iS uw m NM MN 7 Click on the output variable you want to evaluate The output variable appears in the Trace Expression field 8 Click OK PSpice Advanced Analysis Users Guide 245 Chapter 8 Measurement Expressions Product Version 10 5 The Arguments for Measurement Evaluation dialog box reappears with the output variable you chose in the Name of trace to search field Arguments for Measurement E valuation Measurement Expression Maxi Load The Measurement Max has 1 argument Please fill it in now Name of trace to search ViLoad Cancel 9 Click OK Your new measurement expression is evaluated and displayed in the PSpice window 10 Click OK in the Display Measurement Evaluation pop up box to continue working in PSpice Your new measurement expression is saved but does not display in the window The only way to get another graphical display is to redo these steps You can see a numerical evaluation by following the next steps Display Measurement Evaluation F
139. eps B Set tolerances for the RLC components Note For standard RLC components the TOLERANCE property can be used to set tolerance values required for Sensitivity and Monte Carlo Standard RLC components can also be used in the Optimizer B Replace active components with parameterized components from the Advanced Analysis libraries m Add smoke parameters and values to RLC components PSpice Advanced Analysis Users Guide 35 Chapter 2 Libraries Product Version 10 5 Example This example is a simple addition of a parameterized component to a new design We ll add a parameterized resistor to a schematic and show how to set values for the resistor parameters using the property editor and the design variables table Selecting a parameterized component 36 We know the pspice_elem library on the Advanced Analysis library list contains a resistor component with tolerance optimizable and smoke parameters We ll use that component in our example 1 In Capture from the Place menu select Part The Place Part dialog box appears Select resistor Add the from the Li pspice_elem pspice_elem oo Cancel library from the library CAPACITOR Add Library advanls folder PULSE Remove Libray hc 5 Part Search V SIN D ACADENCET41NCAPTURENLIBRARYAPSPICENADVANLSSPSPICE ELEM OLB Ja Note ADVAN LS Libraries Graphic in library path B nma name m Packaging Parts per Pkg 1 Ei Icon tells you
140. er the measurement expressions or traces appears in the Variables drop down list When you select time or frequency as X Axis Variable all the traces added by you in the Measurements tab appear in the drop down list For all other selections of X Axis Variables the measurements added by you in the Measurements tab are listed in the drop down list In the Select Parameter page of the Plot Wizard specify the parameter that will be varied for each trace to be plotted and click Next In cases where there are more than two variable parameters you need to specify a constant value for the PSpice Advanced Analysis Users Guide Product Version 10 5 Viewing the plot Measurements Tab Example Example variable parameters that are not covered in Step 3 or Step 6 Right click on the parameter value and choose Lock Click Finish The complete plot information gets added in the Plot Information tab Select the plot to be displayed in the PSpice probe window From the Analysis drop down menu choose Parametric Plotter gt Display Plot Alternatively right click on the selected row and choose Display Plot The PSpice probe window appears with multiple traces In this section you will use Parametric Plotter to evaluate a simple test circuit for inductive switching This circuit is created using a power mosfet from the PWRMFET OLB The design example is available at tools pspice tutorial capture pspiceaa snu bbe
141. er values will be varied within 10 of the tolerance value Consider that you want to test a resistor of 100k for sensitivity The tolerance value attached to the resistor is 10 By default for sensitivity calculations the value of resistor will be varied from 96K to 104K But if you change thedefault value of Sensitiviy Variation to 1096 the resistor values will be varied from 99K to 101K for sensitivity calculations Relative sensitivity is the percentage of change in a measurement based on a one percent positive change of a component s parameter value For example For each 1 percent change in resistance there may be 2 percent change in voltage The formula for relative sensitivity is Ms Mn Sy To1 Where PSpice Advanced Analysis Users Guide 67 Chapter 3 Sensitivity Product Version 10 5 M the measurement from the sensitivity run for that parameter Mp the measurement from the nominal run Tol relative tolerance of the parameter s Sensitivity Variation Default 40 Relative sensitivity calculations determine the measurement change between simulations with the component parameter first set at its original value and then changed by Sv percent of its positive tolerance Linearity is assumed This approach reduces numerical calculation errors related to small differences For example assume that an analysis is run on a 100 ohm resistor which has a tolerance of 10 percent The maximum value f
142. er you have found commercial values for your design you should run Monte Carlo and Sensitivity to ensure that the design is producible Occasionally the optimization process can find extremely good results but it can be sensitive to even minor changes in parameter values 292 PSpice Advanced Analysis Users Guide Troubleshooting 10 In this chapter B Troubleshooting feature overview on page 293 Q Procedure on page 295 Q Example on page 296 m Common problems and solutions on page 308 Troubleshooting feature overview The Advanced Analysis troubleshooting feature returns you to PSpice to analyze any measurement specification that is causing a problem during optimization Strategy When an Optimizer analysis fails the error message displayed in the output window or a yellow or red flag in the Specifications table shows you which measurement and simulation profile is associated with the failure If the failure is a simulation failure convergence error or a measurement evaluation error the troubleshooting feature can help track down the problem PSpice Advanced Analysis Users Guide 293 Chapter 10 Troubleshooting Product Version 10 5 From the Optimizer tool in Advanced Analysis you can right click on a measurement specification and select Troubleshoot in PSpice PSpice will display two curves one with the data from the original schematic values and one with the data of the last analysis run Workflow Ad
143. ers that have been defined in the schematic appear in the Parameter Selection dialog box For the parameter that you want to vary specify the Sweep Type a In the Parameter Selection dialog box click the Sweep Type grid b From the drop down list select the sweep type as Discrete Linear LogarithmicDec or LogarithmicOct Note Sweep type defines the method used by the Parametric Plotter to calculate variable parameter values To know more about the sweep types see Sweep Types on page 213 To specify the sweep values for the selected parameter click the Sweep Values grid PSpice Advanced Analysis Users Guide Product Version 10 5 Sweep Types The Sweep Settings dialog box appears Sweep Settings 1 x Sweep Type Start Value feno End Value e 0 Step Value emi Total number of steps 23 Cancel 4 Inthe Sweep Settings dialog box the sweep type you selected in the previous step appears in the Sweep Type drop down list box Specify the parameter values that would be used for each parameter during sweep analysis To know more about the sweep types and sweep values to be specified see Sweep Types on page 213 5 Click OK to save your specifications The selected parameters get added in the sweep parameter window When you add the parameters a Sweep Variable is automatically assigned to each of the parameters Sweep Parameters On Off Component Parameter Sweep Variable Sweep
144. esults You can set up the Parametric Plotter to display data in a number of ways Sorting values You can sort the results of the sweep analysis according to the values in any column For example if you want to view the result of keep r4 to a constant value of 39 sort the values in the third column and view the results 222 PSpice Advanced Analysis Users Guide Product Version 10 5 Locking Values Plot Information tab Adding plot Viewing results To sort the values displayed in a column double click on the column name Once the contents of the column are sorted subsequent click on the column name with toggle the order of sorting For example after the Results pane is populated double clicking the column name arranges the values in ascending order Now if you again double click on the column name the column contents willl get arranged in descending order While analyzing the simulation results you can lock the values displayed in one column Once you have locked the values of a column the order in which the values are displayed in that column do not change You can then sort the values in other columns For example you can sort the values of r7 and lock the column If you now sort the values of r6 the values will be sorted for fixed value of r7 To lock the values displayed in a column click the lock icon at the top of the column The Plot Information tab can be used to specify a plot that you want to v
145. et your performance goals NH Smoke warns of component stress due to power dissipation increase in junction temperature secondary breakdowns or violations of voltage current limits PSpice Advanced Analysis Users Guide 15 Ch P Cr 16 apter 1 Introduction Product Version 10 5 m Monte Carlo estimates statistical circuit behavior and yield roject setup Before you begin an Advanced Analysis project you need B Circuit components that are Advanced Analysis ready Only those components that you want tested in Advanced Analysis have to be Advanced Analysis ready See Chapter 2 Libraries Note You can adapt passive RLC components for Advanced Analysis without choosing them from parameterized libraries See Chapter 2 Libraries B A circuit drawn in Capture and successfully simulated in PSpice B PSpice measurements that check circuit behavior critical to your design Circuit with Advanced Analysis ready components STEM ps PSpice Advanced Optimized design Analysis Smoke stress analysis Monte Carlo yield analysis Working PSpice simulation Measurements created in PSpice eating measurement expressions Sensitivity Optimizer and Monte Carlo require measurement expressions as input You should create these measurements expressions in PSpice so you can test the results You can also create measurement expressions in Sensitivity Optimizer or Monte Carlo which can be exported to eac
146. examine the syntax View Measurement E B andwidth 1 db level x2 x1 fDescti Find the difference between the X values where the trace tiDesct first crosses its maximum value minus evel Ymax db level fDesctt with a positive slope and then with a negative slope tiDescti i e Find the db level bandwidth of a signal HArg Name of trace to search H amp rg2t db level down for bandwidth calc WForceDBArgl Search forward level max db_level p 1 Search forward level max db leveln 2 This Measurement is saved in the file ENCadencePSD 32 1 PSpice Common pspice prb Measurement definition fill in the place holders measurement name 1 2 n subarg1 subarg2 subargm marked_point_expression 1 search_commands_and_marked_points_for_expression_1 2 search_commands_and_marked_points_for_expression_2 n search_commands_and_marked_points_for_expression_n Measurement name syntax Can contain any alphanumeric character A Z 0 9 or underscore _ up to 50 characters in length The first character should be an upper or lower case letter Examples of valid function names Bandwidth CenterFreq delay time DBlevel1 258 PSpice Advanced Analysis Users Guide Product Version 10 5 Comments syntax For power users A comment line always starts with an asterisk Special comment lines include the following examples Desc The measurement description
147. f which hides the backgrounds are read only run measurement s trace on the Error and cannot be edited Graph Controlling optimization Pausing stopping and starting You can stop and resume an analysis to explore optimization trends in the Error Graph to reset goals or to change engines when results are not what you expected The analysis will stop saving the optimization data You can also use pause and resume to accomplish the same thing B To start or resume click lp on the top toolbar m To pause click I on the top toolbar 118 PSpice Advanced Analysis Users Guide Product Version 10 5 Example m Tostop click gg on the top toolbar Click to start Click to pause Click to stop optimization optimization optimization ote eer ouwe lt Modified LSQ Assigning available values with the Discrete engine The Discrete engine is used at the end of the optimization cycle to round off component values to the closest values available commercially At the end of the example run Optimization was successful for all the measurement goals and constraints However the new resistor values may not be commercially available values You can find available values using the Discrete engine i SCHEMATIC PSpice Advanced Analysis Optimizer File Edit view Run Analysis Window Help laix Current values may a B xe optimize Mediied La gt 0s IE amp amp Gg I
148. file drop down list and also specify the trace expression or the measurement for which you want to optimize the design 2 Specify the reference file 3 Specify the reference waveform The Ref Waveform drop down list box lists all the reference waveforms present in the reference file that is specified in the previous step 4 Specify the Weight for the specification Specify the relative tolerance To be able to use curve fitting for optimizing your circuit you must have a reference waveform In Advanced Analysis Optimizer the reference waveform is specified in form of multiple data points stored in a reference file A reference file is a text file that contains the reference waveform with respect to a sweep in the tabular form with the data values separated by white spaces blanks tabs or comma An reference file has to have a minimum of two columns one for the sweep data and one for the reference waveform A reference file can have multiple columns Each extra column represents a different reference waveform PSpice Advanced Analysis Users Guide Product Version 10 5 Optimizer procedure overview The format of a multiple column reference file is shown below If the column name is missing Optimizer assigns column name as column number If the grid is blank Optimizer assumes the entry to be Time for transient analysis and Frequency for AC simulation profile Reference Waveforms Waveform Wavefo
149. formance before running Optimizer 4 Click OK Click amp Or From the File menu select Print Click ll Or From the File menu select Save The final results will be saved in the Advanced Analysis profile aap PSpice Advanced Analysis Users Guide Product Version 10 5 Example Optimizing a design using curve fit specifications The design example covered in this section explains how you can use curve fitting to achieve desired response from a multiple feedback two pole active bandpass filter This bandpass filter uses two 7 pin operational amplifiers A plot window template marker Bode Plot dB dual Y axes is added at the output of the second operational amplifier before R7 This marker is used to plot the magnitude and the phase gain of the output voltage The LSQ engine will be used for optimizing this circuit design The design example is available at tools pspice tutorial capture pspiceaa ban dpass Figure 4 1 Bandpass Filter 1 Draw the circuit as shown in Figure 4 1 2 Simulate the circuit From the PSpice menu choose Run 3 The PSpice probe widow appears displaying the simulation results Two traces one for phase gain of the PSpice Advanced Analysis Users Guide 125 Chapter 4 Optimizer Product Version 10 5 output voltage and another for the voltage gain dB of the output voltage are displayed EMATIC1 bias PSpice A D bandpass schemati
150. ge PSpice Advanced Analysis Users Guide Product Version 10 5 Terms you need to understand Terms you need to understand Optimization Optimization is the process of fine tuning a design by varying user defined design parameters between successive simulations until performance comes close to or exactly meets the ideal performance The Advanced Analysis Optimizer solves four types of optimization problems as described in the table shown below Problem Type Optimizer Action Example Unconstrained Reduces the value of a Minimize the propagation minimization single goal delay through a logic cell Constrained minimization Reduces the value of a Minimize the propagation single goal while delay through a logic cell satisfying one or more while keeping the power constraints consumption of the cell less than a specified value Unconstrained least Reduces the sum of the Given a terminator squares1 squares of the individual design minimize the sum errors difference of squares of the errors in between the ideal and the output voltage and measured value for a set equivalent resistance of goals Constrained least Reduces the sum of Minimize the sum of squares squares of the individual squares of the figures of errors for a set of goals merit for an amplifier while satisfying one or design while keeping the more constraints open loop gain equal to a specified value 1 Use unconstrained least squares when fitting mod
151. graph and select CDF graph from the pop up menu From the View menu select Log File Monte Carlo and scroll through the file to the applicable run Can t make user interface do what you want Problem Can t make user interface do what you want Return to top of table Possible cause Solution can t get all my red bar graphs to appear at the top of my Smoke or Sensitivity tables don t want to see the grey bars in Smoke PSpice Advanced Analysis Users Guide Data isn t sorted Average RMS or peak limits that don t apply to your parameter may be selected Click twice on the bar graph column header The first click puts all the red bars at the bottom The second click puts them at the top Double click the message flag column header This will sort the grey bars so they appear at the bottom of the data display or Right click and uncheck the average RMS or peak values on the right click pop up menu 317 Chapter 10 Troubleshooting Problem Can t make user interface do what you want Possible cause Product Version 10 5 Solution Why can t use my Monte Carlo settings and results from PSpice A D Monte Carlo cursor won t drag to a new location The programs are separate and use different input The cursor can be moved but it doesn t use the drag and drop method Advanced Analysis Monte Carlo provides more information and can be run on more than one sp
152. h other but these measurements cannot be exported to PSpice for testing PSpice Advanced Analysis Users Guide Product Version 10 5 Validating the initial project Project setup Before you use Advanced Analysis 1 Make your circuit components Advanced Analysis ready for the components you want to analyze See Chapter 2 Libraries for more information 2 Setup a PSpice simulation The Advanced Analysis tools use the following simulations This tool Works on these PSpice simulations Sensitivity Time Domain transient DC Sweep AC Sweep Noise Optimizer Time Domain transient DC Sweep AC Sweep Noise Smoke Time Domain transient Monte Carlo Time Domain transient DC Sweep AC Sweep Noise 3 Simulate the circuit and make sure the results and waveforms are what you expect 4 Define measurements in PSpice to check the circuit behaviors that are critical for your design Make sure the measurement results are what you expect Note For information on setting up circuits see your schematic editor user guide Project setup on page 16 and Chapter 2 Libraries For information on setting up simulations see your PSpice User s Guide PSpice Advanced Analysis Users Guide 17 Chapter 1 Introduction Product Version 10 5 For information on setting up measurements see Procedure for creating measurement expressions on page 240 Advanced Analysis files The principal files used by Advanced Analysis
153. he 10 point in a positive direction That point s X and Y coordinates will be marked and saved as point 1 The second search function searches forward in the positive direction for the point on the trace where the waveform crosses the 90 mark That point s X and Y coordinates will be marked and saved as point 2 The marked point expression is x2 x1 This means the measurement calculates the X value of point 2 minus the X value of point 1 and returns that number PSpice Advanced Analysis Users Guide 267 Chapter 8 Measurement Expressions Product Version 10 5 268 PSpice Advanced Analysis Users Guide Optimization Engines In this chapter LSQ engine on page 269 Modified LSQ engine on page 282 Random engine on page 287 Discrete engine on page 290 LSQ engine The LSQ engine works with the measurement goals you define minimizing the difference between the present circuit measurements and your goal by adjusting the circuit parameters you have chosen PSpice Advanced Analysis Users Guide 269 Chapter 9 Optimization Engines Product Version 10 5 Principles of operation Parameters The LSQ engine optimizes the design by minimizing the total error Totalerror Each parameter that is varied adds a dimension to the problem In the simple case of two parameters you have a three dimensional problem Complexity increases as you add parameters Local and global minimums Picture the problem in terms of a meta
154. he Optimizer In this method every data point is optimized Therefore the error at each data point should be zero The Optimizer calculates error at each of the reference point and the final error is the RMS of the error at all reference points Note The legacy gear works only if the number of data points to be optimized is less than 250 If the number of data points is more than 250 next gear selected automatically Weighted reference gear In this case the Advanced Analysis Optimizer considers a union of the reference data points as well as simulation data points in the common interval of time or frequency values A PSpice Advanced Analysis Users Guide Product Version 10 5 Optimizer procedure overview weight factor is multiplied to the error at each X In this case Xi will contain both the reference file points and the simulation sweep points but the error is calculated by multiplying the weight factor to the error at each point Therefore the error is Where Wiis the weight that is calculated using the following formula m For data points appearing only in the simulation data W zl 1 m For data points appearing in the reference waveform b 2 imi a Where bz sizeof X ef uu and a sizeof X ef The sizeof function returns the size of the vector X ref sim indicate the union of the reference data points as well as simulation data points in a common interval Note The weighted reference gear is sa
155. he Parametric Plotter is more than 2 If the sweep type is LogarithmicDec the parameter values are varied as a function of 1n 10 For Logarithmic decimal Sweep you need to specify the Start Value End Value and number of points per decade Number of points per decade is number of points between the start value and 10 times start value For example if the start value is 10 number of points per decade is 5 this implies that for sweep analysis the Parametric Plotter will pick up 5 value between 10 and 100 with 100 being the fifth value During the analysis the parameter value in increased by a factor which is calculated using the following equation factor exp 1n 10 N Where N Number of points per decade Example If you specify the start value as 10 end value as 100 and number of points per decade as 5 the parameter values used for sweep analysis will be 10 15 8489 25 1189 39 8107 63 0957 and 100 PSpice Advanced Analysis Users Guide 215 Chapter 7 Parametric Plotter Adding sweep parameters Product Version 10 5 In the Sweep Parameters window add the parameters values that you want to vary during the sweep analysis 1 3 216 In the Sweep Parameters window click the Click here to import a parameter from the design property map row The Parameter Selection dialog box appears with a list of components and the parameters for which you can sweep the parameter values Only the component paramet
156. help find an acceptable answer Three good approaches are B Start from different initial parameter values m Change a goal to a more optimistic or less optimistic value This changes the shape of the terrain or total error surface B Stop the Optimizer and then restart it This throws out the slope gradient information forcing the step size to be a guess which could get you out of the local minimum PSpice Advanced Analysis Users Guide 273 Chapter 9 Optimization Engines Product Version 10 5 Parameter mapping For reasons of numerical accuracy and solution stability the LSQ optimizing algorithm does not work directly with schematic parameter values Instead a mapping and normalizing algorithm relates the schematic parameters to the variables that are adjusted during optimization The mapping and normalizing restricts the parameter values to a range that you specify and concentrates adjustments on the center of the range The LSQ engine uses a multiplier and an arctan function for mapping the values adjusted by the optimizer to the schematic parameter values The arctan function is shown in the following figure 274 PSpice Advanced Analysis Users Guide Product Version 10 5 LSQ engine Arctan Mapping Function Curve Normalized parameter Optimizer adjusted parameter In the figure the value adjusted in the Optimizer is the x axis Potentially it can have any value from negative infinity to positive infinity In p
157. hich tolerances are specified appear in the Parameters window Note Sensitivity analysis can only be run if tolerances are specified for the component parameters In case you want to remove a parameter from the list you can do so by using the TOL ON OFF property In the schematic design set the value of TOL ON OFF property attached to the instance as OFF If there is no TOL ON OFF property attached to the instance of the device attach the property and PSpice Advanced Analysis Users Guide 45 Chapter 3 46 Sensitivity Product Version 10 5 set its value to OFF This is so because if the tolerance value is specified for a parameter and TOL_ON_OFF property is not attached to the component by default Advanced Analysis assumes that the value of TOL_ON_OFF property is set to ON SCHEMATIC1 PAGE1 CAPACITOR CAPACITOR Norma VOLTAGE P_i os SSS ae meal i In case of hierarchical designs the value of the TOL_ON_OFF property attached to the hierarchical block has a higher priority over the property value attached to the individual components For example if the hierarchical block has the TOL_ON_OFF property value set to OFF tolerance values of all the components within that hierarchical design will be ignored Specifications Window In the Specifications window add measurements for which you want to analyze the sensitivity of the parameters You can either import the me
158. ht to revoke this authorization at any time and any such use shall be discontinued immediately upon written notice from Cadence Disclaimer Information in this publication is subject to change without notice and does not represent a commitment on the part of Cadence The information contained herein is the proprietary and confidential information of Cadence or its licensors and is supplied subject to and may be used only by Cadence s customer in accordance with a written agreement between Cadence and its customer Except as may be explicitly set forth in such agreement Cadence does not make and expressly disclaims any representations or warranties as to the completeness accuracy or usefulness of the information contained in this document Cadence does not warrant that use of such information will not infringe any third party rights nor does Cadence assume any liability for damages or costs of any kind that may result from use of such information Restricted Rights Use duplication or disclosure by the Government is subject to restrictions as set forth in FAR52 227 14 and DFAR252 227 7013 et seq or its successor PSpice Advanced Analysis Users Guide Contents Before you DEGIN 0 ccc ccc eee e eens 9 Welcome arre aroda Boe Sekt Sia Peet entra eh Re pa ee eee NR hot Blea SI oh oe 9 How to use this guide 3s emer xe aera ha fu d p SURE RR teens ith Aes ais ae eA pne qu 10 Symbols and COBVertllOlis
159. ic Plotter Each run of the parametric plotter is indicated by a row in the Results tab Therefore if for the complete analysis Parametric plotter completes 100 runs there will be 100 rows in the results tab The number of columns in the results tab is equal to the number of variable parameters and the number of measurements or the traces to be evaluated There is one column each for a variable parameter and measurement expression to be evaluated PSpice Advanced Analysis Users Guide 221 Chapter 7 Parametric Plotter Product Version 10 5 In case of traces instead of the measurement value a trace is generated for each run of Parametric Plotter As traces cannot displayed on the Results tab therefore instead of each trace a yellow colored bitmap is visible To view the complete trace double click the yellow colored bitmap in the Results pane The trace gets displayed in the PSpice Probe window Measurement function to be evaluated Trace to be evaluated Variable Parameters r wvalue tran sim risetime s tran sim v r a HX oo ean ee 0 1895523701161 0 1895536451509 0 1923795301141 0 1895510845215 0 1895523701005 0 1895536476968 0 1923795300981 0 1895510729041 0 1895523700831 1148698354997 1148698354997 1148698354997 1148698354997 1319507910773 1319507910773 Values of r4 varied for a constant value of r7 and r6 Double click to view the corresponding trace Analyzing R
160. iew in the Probe window Using the Plot Information tab you can view multiple traces in one window This is useful when you want to view the result of varying a parameter on the output At any given point of time you can add a maximum of four plots 1 Fromthe Analysis menu select Parametric Plotter Add New Plot PSpice Advanced Analysis Users Guide 223 Chapter 7 224 Parametric Plotter Product Version 10 5 The Plot Wizard appears Note Alternatively right click on the Plot Information tab and select Add Plot In the Select Profile page of the Plot Wizard specify the simulation profile for which you want the profile to be created and click Next In the select X Axis Variable page of the wizard specify the variable parameter that you want to plot on the X axis of the plot From the variables drop down list you can select any of the sweep parameter or the measurements that you specified in the Measurements tab Besides the variable parameter and the measurements the drop down list has an extra entry which is time or frequency When you select a transient profile you can select Time as the X Axis variable and plot out results against time When you select a AC profile you can select Frequency as the X Axis variable Click Next In the Select Y Axis Variable page select the variable to be plotted in the Y axis and click Next Depending on your selection in the previous page of the Plot wizard eith
161. ight click on the graph and Hover your mouse above use pop up menu to toggle the bin details will appear to Percent Y axis in a pop up message This pop up menu appears when you right click on the graph Select to toggle to the PDF Graph Select to recalculate Select to toggle between results for a different absolute runs and min max range percentage of runs 1 Right click on the graph and select Percent Y axis from the pop up menu PSpice Advanced Analysis Users Guide 199 Chapter 6 Monte Carlo Product Version 10 5 The Y axis units changes from Number of Runs to Percent of Runs Probability Density Graph Runs 1 to 100 Percent of Runs Max DB V Load Y axis changed to Percent of Runs 2 From the Edit menu select Profile Settings click the Monte Carlo tab select the Number of Bins text box and type the number 20 in place of 10 Notice the higher level of detail on the PDF graph Probability Density Graph Runs 1 to 100 Number of Runs B3E B5 BD B B B B 38 9 9 92 83 94 95 8B 97 9B 923 10 1011 182 10 3 10 4 105 105 S19 ee Max DB V Load EX Same statistical results but 20 bins are specified twice as many as first PDF graph 3 Right click on the graph and from the pop up menu select Zoom In to view a specific range 4 Select Zoom Fit to show the entire graph with cursors 5 Click the Max cursor to select it it turns red when selecte
162. ilable in the design variables table includes variable names for tolerance and smoke parameters For example RTOL is a variable name in PSpice Advanced Analysis Users Guide 33 Chapter 2 34 Libraries Product Version 10 5 the design variables tables which can be used to set POSTOL and NEGTOL tolerance values on all your circuit resistors 1 2 3 From Capture s Place menu select Part Add the PSpice SPECIAL library to your design libraries Select the Variables component from the PSpice SPECIAL library Click OK A design variable table of parameter variable names will appear on the schematic Double click on a number in the design variable table The Display Properties dialog box will appear Edit the value in the Value text box Click OK The new numerical value will appear on the design variables table on the schematic and be used as a global value for all applicable components Parameter values set on a component instance will override values set in the design variables table PSpice Advanced Analysis Users Guide Product Version 10 5 Modifying existing designs for Advanced Analysis Modifying existing designs for Advanced Analysis Existing designs that you construct with standard components will work in Advanced Analysis however you can only perform Advanced Analysis on the parameterized components To make sure specific components are Advanced Analysis ready parameterized do the following st
163. imizer from the drop down list on the top toolbar This switches the active window to the Optimizer view where you can double check that your critical parameters are listed in the Optimizer Parameters table Click the Sensitivity tab at the bottom of the Optimizer Specifications table This switches the active window back to the Sensitivity tool Click amp b Or From the File menu select Print PSpice Advanced Analysis Users Guide Product Version 10 5 Sensitivity procedure Saving results Click fed Or From the File menu select Save The final results will be saved in the Advanced Analysis profile aap Example The Advanced Analysis examples folder contains several demonstration circuits This example uses the RFAmp circuit The circuit contains components with the tolerances of their parameters specified so you can use the components without any modification Two PSpice simulation profiles have already been created and tested Circuit measurements entered in PSpice have been set up and tested Note See Chapter 2 Libraries for information about setting tolerances for other circuit examples Setting up the circuit in the schematic editor 1 In your schematic editor browse to the RFAmp tutorials directory target directory PSpice tutorial Capture pspiceaa rfamp PSpice Advanced Analysis Users Guide 53 Chapter 3 Sensitivity Product Version 10 5 2 Open the RFAmp project Assign global
164. ine 196 Setting up component parameters 1 Inthe Parameters table click on the row containing the text Click here to import pap ett Parameters Hext Run Original Click here to import a parameter from the design property map Click PSpice Advanced Analysis Users Guide 111 Chapter 4 Optimizer Product Version 10 5 The Parameters Selection dialog box appears Parameters Selection H XI Component Parameter Original Min Max C1 VALUE 10n In 100n C3 VALUE 470n 4 n 4 7000u C4 VALUE 10u lu 100u C6 VALUE 470n 4 n 4 7000u C VALUE 470n 4 n 4 7000u R1 VALUE 24k 2 4000k 240k R2 VALUE 3k 300 30k 4 7000k Hold down the CTRL key and click to add multiple components To select multiple items hold down the CTRL key then click each entr Hold down the SHIFT key to select or deselect adjacent items Cancel 2 Highlight these components in the Parameters Selection dialog box Q R6 the 470 ohm resistor a R4 the 470 ohm resistor Q R8 the 3 3 ohm resistor 3 Click OK The components are now listed in the Parameters table 4 Inthe Parameters table Min and Max columns make these edits Q R8 min value 3 max value 3 6 Q R6 min value 235 max value 705 Q R6 min value 235 max value 705 112 PSpice Advanced Analysis Users Guide Product Version 10 5 Example This tightens the range the engine will vary the resistance of each resistor for more efficient optimi
165. ine makes a final run that lets you review the results in both the Optimizer and the output PSpice Advanced Analysis Users Guide Product Version 10 5 Discrete engine tools If the results of the discrete analysis are not acceptable the design can be optimized again to find another global minimum that might be less sensitive PSpice Advanced Analysis Users Guide 291 Chapter 9 Optimization Engines Product Version 10 5 Commercially available values Advanced Analysis includes discrete tables of commercially available values for resistors capacitors and inductors These tables are text files with a table file extension See Assigning available values with the Discrete engine on page 105 for instructions on selecting the discrete tables provided with Advanced Analysis Optimizer In addition you can add your own discrete values tables to an Advanced Analysis project using the dialog box shown below To know more about the adding user defined discrete value tables see Adding User Defined Discrete Table on page 132 Profile Settings B xj ptimizer Monte Carlo Smoke Simulation Engine The Discrete Engine is used at the end of the optimization cycle to round off component values to commercially available values Curve Fit Error Discrete T able Alias Reference Only Uses only Part Type reference file data points for error calculation Cancel Set Defaut Help Aft
166. inition and then you select an output variable to measure The two combined become a measurement expression Note For the current design example work in the Simulation Results view in PSpice 1 Inthe side toolbar click on dsl 2 From the Trace menu in PSpice select Measurements 242 PSpice Advanced Analysis Users Guide Product Version 10 5 The Measurements dialog box appears Trace Plot Tools Window Help gs E Add Trace Insert Delete All Traces Chrl Delete Undelete Traces trl FFr Fourier Performance Analysis Cursor Macros Measurements Ai Evaluate Measurements Example 3 Select the measurement definition you want to evaluate 4 Click Eval evaluate Measurements Bandwidth Bandwidth Bandpass 3dB Bandwidth Bandpass 3dB xXRange CenterFrequency CenterFrequency Range Conversion ain ConversionG ain Fiange Cutoff Highpass 3dB Cutoff Highpass 3dB xXRange Cutoff_Lowpass_3dB Cutoff_Lowpass_3dB_Range DutyCycle DutyCycle_Range Falltime_NoOvershoot Falltime_StepResponse Falltime_StepResponse_Range GainMarain Max o S lt View Edit Delete Load T3111 The Arguments for Measurement Evaluation dialog box appears PSpice Advanced Analysis Users Guide 243 Chapter 8 Measurement Expressions Product Version 10 5 5 Click the Name of trace to search button The Traces for Measurement Arguments dialog box appears Argum
167. ions Find in Design Derating d db cut Copy B Paste Delete PSpice Advanced Analysis Users Guide 147 Chapter 5 148 Smoke Product Version 10 5 In the Max column check the bar graphs Q Red bars show values that exceed safe operating limits Q Yellow bars show values getting close to the safe operating limits between 90 and 100 percent of the safe operating limits Q Green bars show values well within the safe operating limits less than 90 percent of the safe operating limits Q Grey bars indicate that limits are not available for the parameters Safe operating limit Red bar exceeds the limit Yellow bar is within 9096 of the limit Green bar is anywhere below 90 of the limit The value in the Max column is calculated using the following formula 5 1 Max Actual operating Value Safe operating limit 100 Where Actual operating WI is displayed in the Measured value Value column B iscalculated by the simulation controller PSpice Advanced Analysis Users Guide Product Version 10 5 Example Safe operating IW is displayed in the Max limit Derating column is MOC derating factor MOC or the Maximum Operating Condition is specified is the vendor supplied data sheet B derating factor is specified by the users in the Derating column The value calculated using the Equation 5 1 on page 148 is rounded off to the nearest integer larger than the calculated value
168. ircuit in the schematic editor on page 139 and Running Smoke on page 140 Controlling smoke on individual design components 142 You can use the SMOKE ON OFF property to control whether or not you want to run smoke analysis on individual devices or blocks in a schematic If you attach the SMOKE ON OFF property to the device instance for which you do not want to perform the smoke analysis and set the value to OFF the smoke analysis would not run for this device This property can also be used on hierarchical blocks The value of the SMOKE ON OFF property attached to the parent block has a higher priority over the property value attached to the individual components PSpice Advanced Analysis Users Guide Product Version 10 5 Smoke procedure Selecting other deratings To select other deratings 1 Right click and from the pop up menu select Derating 2 Select one of the three derating options on the pull right menu a No Derating Q Standard Derating Q Custom Derating Files 3 Click on the top toolbar to run a new Smoke analysis with the revised derating factors New results appear For information on creating a custom derating file see our technical note posted on our web site at www orcadpcb com PSpice Advanced Analysis Users Guide 143 Chapter 5 Smoke Product Version 10 5 Example Overview This example uses the tutorial version of RFAmp located at lt target directory gt PSpice tutorial capture pspiceaa rf
169. ired for Advanced Analysis Optimizer is the value for the component Examples are listed below Part Optimizable Property Name Value Resistor VALUE 10K Inductor VALUE 33m Capacitor VALUE 0 1u PSpice Advanced Analysis Users Guide Product Version 10 5 Preparing your design for Advanced Analysis For example For RLC components the parameters required for Advanced Analysis Smoke are listed below The values shown are those that can be set using the design variables table See Using the design variables table on page 33 Part Smoke Property Name Value Resistor MAX TEMP RTMAX Resistor POWER RMAX Resistor SLOPE RSMAX Resistor VOLTAGE RVMAX Inductor CURRENT DIMAX Inductor DIELECTRIC DSMAX Capacitor CURRENT CIMAX Capacitor KNEE CBMAX Capacitor MAX TEMP CTMAX Capacitor SLOPE CSMAX Capacitor VOLTAGE CMAX If you use RLC components from the analog library you will need to add parameters and set values however instead of setting values for the POSTOL and NEGTOL parameters you set the values for the TOLERANCE parameter The positive and negative tolerance values will use the value assigned to the TOLERANCE parameter Using the design variables table The design variables table is a component available in the installed libraries that allows you to set global values for parameters For example using the design variables table you can easily set a 5 positive tolerance on all your circuit resistors The default information ava
170. is Starting lick to start or resume Controlling Measurements Click to remove this check Click here to edit the mark and exclude this measurement measurement from analysis expression Specifications 150 5788meg Y vw ri smp schematict bandwidth v losc 3 f v jw rf amp schematict minctO logt O v indi jw rt_amp schematict max v onoise 62 PSpice Advanced Analysis Users Guide Product Version 10 5 Sensitivity procedure Adjusting component values In the RF example we will not change any component parameters With another example you may decide after reviewing sensitivity results that you want to change component values or tighten tolerances You can use Find in Design from Advanced Analysis to return to your schematic editor and locate the components you would like to change 1 Inthe Parameters table highlight the components you want to change 2 Right click the selected components A pop up menu appears Find in Design Display d Bar Graph Style d Send To Optimizer d Cut Copy ir Paste Delete 3 Leftclick on Find in Design PSpice Advanced Analysis Users Guide 63 Chapter 3 Sensitivity Product Version 10 5 The schematic editor appears with the components highlighted 4 Change the parameter value in the schematic editor 5 Rerun the PSpice simulation and check results 6 Rerun Sensitivity Sending parameters t
171. is Users Guide Product Version 10 5 Local minima and searching LSQ engine For the first step no slope gradient is known so a guess on the step size is made based on the internal parameters in the LSQ engine Often the LSQ engine attempts to take several steps based on the sensitivity data or the results of each step but only one step is accepted for each iteration As the LSQ engine completes an iteration it begins to estimate the slope of the mountain This aids it in determining the size of the next step and whether the bottom of the valley local minimum has been found When the engine finds a local minimum it stops and reports the position and total error This may or may not be the optimum solution or an acceptable solution Finding the optimum solution may be difficult in complex designs with many variables in the design space Changing starting parameters constraints and goals can be used to search more of the design space in an attempt to find a better solution This extended searching of the design space usually is not needed because the LSQ engine can easily find a global minimum that is not the optimum solution yet is acceptable Sometimes the local minimum is not acceptable and modifications to the optimization problem might help find an acceptable global minimum This limitation is shared by all minimizing algorithms like LSQ If the LSQ engine gets stuck in an unacceptable local minimum several options can
172. is Users Guide Product Version 10 5 S Safe Operating Limits SOLs sensitivity skewed distribution function Smoke analysis specification U uniform distribution function S measurement Glossary Maximum safe operating values for component parameters in a working circuit with safety factors derating factors applied Safety factors can be less than or greater than 100 percent of the maximum operating condition depending on the component The change in a simulation measurement produced by a standardized change in a parameter value A acasureiedt A parameter See also relative and absolute sensitivity Related to Monte Carlo This is a type of distribution function that favors one end of the values range With this distribution function there is a higher probability that Monte Carlo will choose values from the skewed end of the tolerance range when picking parameter values for analysis A set of safe operating limit calculations Uses component parameter maximum operating conditions MOCs and safety factors derating factors to calculate if each component parameter is operating within safe operating limits Also referred to as stress analysis A goal for circuit design In Advanced Analysis a specification refers to a measurement expression and the numerical min or max value specified or calculated for that expression See flat distribution function PSpice Advanced Analysis Users Guide 345
173. is y mint O log1 Of v inoise v inoise 3 28 max onoise The measurements in PSpice give the results we expected PSpice Advanced Analysis Users Guide 109 Chapter 4 Optimizer Product Version 10 5 Setting up Optimizer in Advanced Analysis Opening Optimizer in Advanced Analysis From the PSpice menu in your schematic editor select Advanced Analysis Optimizer The Optimizer tool opens Error Graph Ws rf amp SCHEMATICI PSpice Advanced Analysis Optimizer Elie Edit View Run Analysis Window Help isi xi Hu ce O pimes gt Modiied LSQ J gt 1 Ie amp Gy Gy t Error Graph Parameters Next Run PS Insertion On Off Component Parameter Min Max Original Current y row 196 Click here to import a parameter from the design property map Specification table iex Z 05 Parameters E table Z 0 N N Run Number 4 Specifications Next Run Output window For Help press F1 Cl T ZA Selecting an engine 1 Click on the drop down list to the right of the Optimizer tool name 110 PSpice Advanced Analysis Users Guide Product Version 10 5 Example A list of engines appears Click to display drop down list IB File Edit View Run Analysis Window Help a E amp d ge optimize Modified LSQ b Modified LSU LSQ Error Graph Random Discrete 2 Select the Modified LSQ eng
174. istance Case to Ambient degC W RJC IGBT Thermal resistance Junction to Case degC W TJ IGBT Maximum junction temperature degC VCE IGBT Maximum collector emitter V VCG IGBT Maximum collector gate voltage V VGEF IGBT Maximum forward gate emitter voltage V VGER IGBT Maximum reverse gate emitter V ID JFET or MESFET Maximum drain current A IG JFET or MESFET Maximum forward gate current A PDM JFET or MESFET Maximum power dissipation W PSpice Advanced Analysis Users Guide 157 Chapter 5 Smoke Smoke Parameter Name and Symbol Semiconductor Product Version 10 5 Property Name Component Maximum Operating Condition RCA JFET or MESFET Thermal resistance Case to Ambient degC W RJC JFET or MESFET Thermal resistance Junction to Case degC W TJ JFET or MESFET Maximum junction temperature degC VDG JFET or MESFET Maximum drain gate voltage V VDS JFET or MESFET Maximum drain source voltage V VGS JFET or MESFET Maximum gate source voltage V ID MOSFET or Maximum drain current A Power MOSFET IG MOSFET or Maximum forward gate current A Power MOSFET PDM MOSFET or Maximum power dissipation W Power MOSFET RCA MOSFET or Thermal resistance Case to Ambient Power MOSFET degC W RJC MOSFET or Thermal resistance Junction to Case Power MOSFET degC W TJ MOSFET or Maximum junction temperature degC Power MOSFET VDG MOSFET or Maximum drain gate voltage V Power MOSFET VDS MOSFET or Maxim
175. ith 50 ohm source and load impedances It includes the circuit schematic PSpice simulation profiles and measurements Note For a completed example see target directory gt PSpice Capture_Samples AdvAnIs RFAmp directory Setting up the circuit in the schematic editor 188 1 In your schematic editor browse to the RFAmp tutorials directory target directory PSpice tutorial Capture pspiceaa rfamp 2 Open the RFAmp project PSpice Advanced Analysis Users Guide Product Version 10 5 Example The RF amplifier circuit example RF Amplifier PEE Di Soke Lim te Rhe 0 25 RSMAX 0 005 RTMAX 200 Tok raiz lux 12 CTOL 10 Chiax 50 RTOL 10 CBMAX 125 LTOL 0 CSMAX 0 005 VTOL 0 CTMAX 125 IT L D CIM X 1 b LMWH 5 Uzer vWarbes Dbk 300 Ihde 1 Ria Ca yyy 0 fu 700 f In j r W We re TRAN Sind Sm 1Meg Am be o oO s 3 Select the SCHEMATIC1 AC simulation profile PSpice Advanced Analysis Users Guide 189 Chapter 6 Monte Carlo Product Version 10 5 The AC simulation included in the RF amp example Simulation Settings AC E m x AC Sweep Type Linear Start Frequency 1 k ptions Logarithmic End Frequency hao General Settings Decade Points Decade fo Monte Carlo Worst Case Parametric Sweep Notes Analysis Temperature Sweep Save Bias Point v Enabled Dutput Voltage ViLoad Load Bias Point IA Source v2 Inte
176. ith type as Trace Running Parametric Plotter 220 After you have specified the measurements and the list of variable parameters run the Parametric Plotter From the Run drop down menu choose Start Parametric Plotter Note Alternatively click the Run button on the toolbar or PSpice Advanced Analysis Users Guide Product Version 10 5 Viewing results press lt CTRL gt lt R gt keys For optimized performance of Parametric Plotter maximum number of parametric sweeps supported in one session is 500 If for your selection of parameters and measurements the total number of sweeps required is greater than 500 an error message is displayed in the Output Window and analysis stops As the simulation progresses the Output Window also shows the profile selected and the number of sweep run being executed f Important The Number of parametric sweeps required which is displayed in the Output window should be interpretted as the number of sweeps required per profile The total number of sweeps required is calculated separately for each profile Viewing results The results of the parametric sweep analysis are displayed in form of a spread sheet in the Results tab of the Measurement window For the same results you can define plot information using the Plot Information tab The plot information is displayed in the PSpice Probe window Results tab The results tab displays the simulation result for each run of the Parametr
177. izer will not meet all of the goals and constraints In these cases optimum performance is the best compromise solution that is the solution that comes closest to satisfying each of the goals and PSpice Advanced Analysis Users Guide Product Version 10 5 Evaluation Trace function Goal function Terms you need to understand constraints even though it may not completely satisfy any single one An evaluation is an algorithm that computes a single numerical value which is used as the measure of performance with respect to a design specification The Optimizer accepts evaluations in one of these three forms m Single point PSpice A DAMS trace function m PSpice A DAMS goal function m Expression based on a combination of functions For example max X max Y Given evaluation results the Optimizer determines whether or not the changes in parameter values are improving performance and determines how to select the parameters for the next iteration A trace function defines how to evaluate a design characteristic when running a single point analysis such as a DC sweep with a fixed voltage input of 5 V For example V out to measure the output voltage I d1 to measure the current through a component Note Refer to the online PSpice A D Reference Guide for the variable formats and mathematical functions you can use to specify a trace function A goal function defines how to evaluate a design characteristic when
178. know more about the distribution functions see the application note named Specifying Advanced Analysis Monte Carlo Distribution Functions at www orcadpcb com Finally the device_max_ops section displays the maximum operating values for each of the smoke parameters If a smoke parameter for a model does not appear in this list the default value as listed in the template property file is used The device pre smoke section The device pre smoke section is present in the device property files of all the non parameterized PSpice model libraries provided by OrCAD and the libraries that have been created or edited using the Model Editor The device pre smoke section lists the default mapping between the node names and the corresponding port names in the part symbol This section is copied from the pre smoke section of the template property file The entries in the device pre smoke section have higher precedence than the default values specified in the pre smoke section For the non parameterized models the port names entered by users in the Test Node Mapping section are written in the device pre smoke section Users can get the port names of a part by opening the symbol in a schematic editor A part of PSpice Advanced Analysis Users Guide 335 Chapter A Property Files Product Version 10 5 the BIPOLAR PRP file with the device pre smoke section is shown below device pre smoke TERM IC C TERM IB B NODE VC C NODE VB
179. l E2 rt_amp schematict max v onoise Snj Censtremt 20 Click here to import a measurement created within PSpice Click a cell to type in a value Select number and edit It is recommended that you complete the steps for setting up component parameters and measurement specifications In case you choose not to perform the Steps you can use the SCHEMATIC1_complete aap file located at tools pspice tutorial capture pspic eaaNrfampNrf amp PSpiceFilesNSCHEMATIC 1 To use the aap file provided with the design example rename SCHEMATIC1 complete aap to SCHEMATICI aap 116 PSpice Advanced Analysis Users Guide Product Version 10 5 Example Running Optimizer Starting a run Click I on the top toolbar File Edit View Run Analysis Window Help sua we O ptmizer v Moditied LSQ bum Click to start optimization The optimization analysis begins The messages in the output window tell you the status of the analysis A nominal run is made with the original component parameter values As the optimization proceeds the Error Graph shows a plot with an error trace for each measurement Data in the Parameters and Specifications tables is updated Optimizer finds a solution after five runs Displaying run data Place your cursor anywhere in the Error Graph to navigate the historical run data The Parameters and Specifications tables display the corresponding data calc
180. last completed run number appears in the output window 2 Click the Ef or to resume calculations Stopping A Click Bi on the top toolbar If a Sensitivity analysis has been stopped you cannot resume the analysis Sensitivity does not save data from a stopped analysis Starting Click to start or restart Controlling measurement specifications Q Toexclude a measurement specification from Sensitivity analysis click on the applicable measurement row in the Specifications table This removes the check and excludes the measurement from the next Sensitivity analysis Q To add a new measurement click on the row containing the text Click here to import a measurement created within PSpice The Import Measurement s dialog box appears 50 PSpice Advanced Analysis Users Guide Product Version 10 5 Sensitivity procedure Or Right click on the Specifications table and select Create New Measurement The New Measurement dialog box appears See Procedure for creating measurement expressions on page 240 Q To exporta new measurement to Optimizer or Monte Carlo select the measurement and right click on the row containing the text Click here to import a measurement created within PSpice Select Send To from the pop up menu Adjusting component values Varying the tolerance range Use Find in Design from Advanced Analysis to quickly return to the schematic editor and change component
181. lo Pausing stopping and starting Click to start Morte Cato z hd T m Click to stop Click to pause Pausing and resuming 1 Click JJ on the top toolbar The analysis stops available data is displayed and the last completed run number appears in the output window PSpice Advanced Analysis Users Guide 205 Chapter 6 Monte Carlo Product Version 10 5 2 Click Ef or to resume calculations The title and the messages in the output Partial results compare window show how the number of runs made these with final 100 run before pausing results EA Fie Edt View Bun Analysis Window Help ala xi AS A E z Wna jlssaljsr Probability Density Graph Runs 1 to 52 F Number of Runs El Statistics E Raw Meas On Off rf an tic1 3 3699 9 rf_amp schematic1 i 145 0557meg 151 3316meq rf amp schematic1 minctO lfat v noiseY 3 8855 4 1688 rf amp schematic1 max v noise 4 2096n 44312n Click here to import a measurement created within PSpice Ka hd hd hal 4 Monte Carlo F Monte Carlo run 41 Monte Carlo run 42 Monte Carlo run 43 Monte Carlo run 44 Monte Carlo run 45 Monte Carlo run 46 Monte Carlo run 47 Monte Carlo run 48 Monte Carlo run 49 Monte Carlo run 50 Monte Carlo run 51 Monte Carlo run 52 Analysis stopped Monte Carlo paused Resume or reset pause to continue the ana
182. lts 49 negative 48 overview 41 procedure 44 relative 67 relative sensitivity 60 results 47 setting up in Advanced Analysis 45 setting up the circuit 44 strategy 43 workflow 44 worst case maximum measurements worst case minimum measurements 68 zero results 49 setting up the Monte Carlo tool 178 the Optimizer tool 83 the Sensitivity tool 45 single point analyses 77 skewed distribution function 345 smoke allowable PSpice simulations 17 analysis runs 138 changing derating options 151 deratings 143 example 145 looking up parameter names 154 overview 137 procedure 140 startingarun 146 strategy 138 viewing results 147 5 o Co Oo workflow 139 smoke parameters 154 opamps 159 passive components 155 RLCs 155 semiconductors 156 smoke results display options temperature parameters only 149 values 147 smoke setup options custom derating 153 no derating 151 standard derating 151 specification 74 conflicting 76 Product Version 10 5 PSpice Advanced Analysis Users Guide See Also constraint See Also goal Standard Derating selecting the option 151 stress analysis see Smoke sweep parameters add 216 sweep type 213 discrete 213 linear 214 logarithmicDec 215 logarithmicOct 214 syntax measurement definition comments 259 measurement definition example 260 266 measurement definition marked point expressions 259 measurement definition names 258 measurement definition search command 260 measurement definitions
183. luation dialog box appears 4 Click the Name of trace to search button The Traces for Measurement Arguments dialog box appears Note You will only be using the Simulation Output Variables list on the left side Ignore the Functions or Macros list 5 Uncheck the output types you don t need if you want to simplify the list 6 Click on the output variable you want to evaluate The output variable appears in the Trace Expression field PSpice Advanced Analysis Users Guide 241 Chapter 8 Measurement Expressions Product Version 10 5 7 Click OK The Arguments for Measurement Evaluation dialog box reappears with the output variable you chose in the Name of trace to search field 8 Click OK Your new measurement expression is evaluated and displayed in the PSpice window 9 Click OK in the Display Measurement Evaluation pop up box to continue working in PSpice Your new measurement expression is saved but it no longer displays in the window The only way to get another graphical display is to redo these steps You can see a numerical evaluation by following the next steps Viewing the results of measurement evaluations 1 From the View menu in PSpice select Measurement Results The Measurement Results table displays below the plot window 2 Click the box in the Evaluate column The PSpice calculation for your measurement expression appears in the Value column Example First you select a measurement def
184. lysis Stopping A Click Bi on the top toolbar Note Mont Carlo does not save data from a stopped analysis After stopping you cannot resume the same analysis Starting Click to start or restart 206 PSpice Advanced Analysis Users Guide Product Version 10 5 Example Changing components or parameters When running other examples if you do not get the results you want go to the schematic editor and change circuit information 1 Try adifferent component for the circuit Or Change the tolerance of a parameter on an existing component 2 Rerun the PSpice simulation and verify that the results are what you expect 3 Rerun Monte Carlo using the settings saved from the prior analysis 4 Review the results Controlling measurement specifications If you do not get the results you want and your design specifications are flexible you can change a specification or delete a measurement and rerun Monte Carlo analysis Cumulative Distribution Graph Runs 1 to 100 Percent of Runs cen el E 84 85 86 87 88 89 9 91 92 93 94 95 96 97 98 99 10 101 102 10 3 10 4 10 5 106 10 7 10 8 Max DB V Load o Statistics E Raw Meas Click here to remove the Click on the dotted box and edit Edit Cursor Min and Cursor Max check mark and exclude the measurement expression values on the table rerun Monte the measurement from Carlo observe new results further analysis PSpice Advanced Analysis Users Guide 2
185. m Gaussian Normal Bimodal and Skewed distribution functions See also cumulative distribution function PSpice Advanced Analysis Users Guide Product Version 10 5 Discrete engine discrete values table error graph F flat distribution function G Gaussian distribution function Glossary Related to the Optimizer The Discrete engine is a calculation method that selects commercially available values for components and uses these values in a final optimization run The engine uses default tables of information provided with Advanced Analysis or tables of values specified by the user For a single component such as a resistor a discrete values table is a list of commercially available numerical values for that component Discrete values tables are available from manufacturers and several tables are provided with Advanced Analysis A graph of the error between a measurement s goal or constraint and the calculated value for the measurement Sometimes expressed in percent Error Calculated meas value Goal value Goal value Error Calculated meas value Constraint Constraint Also known as Uniform distribution function Related to Monte Carlo This is the default distribution function used by Advanced Analysis Monte Carlo For a Flat Uniform distribution function the program has an equal probability of picking any value within the allowed range of tolerance values Also known as Normal
186. mation Select Y Axis Variable x Select the variable to be plotted on Y Axis Y Axis Variables transient sim overshoot v Il 2 transient sim yatlastx avalw r2 coc Hee 5 Select cl value as the parameter to be varied such that for each possible value of this parameter you have a unique x y trace and click Next Plot Information Select Parameter gt Select the variable to be plotted as a parameter Parameter Variables rese ae 6 The remaining sweep parameters and their possible values are listed For each parameter select a constant value to be used for drawing the trace s To assign a PSpice Advanced Analysis Users Guide Product Version 10 5 Example constant valueto param trise right click on 10n and lock it Plot Information Set Constant Values right mouse button To the remaining parameters assign a constant value by using Parameter Constants c param trise 7 Similarly assign a constant value to q1 cgso Click Finish Plot Information Set Constant Values gt To the remaining parameters assign a constant value by using right mouse button a ql cgso AM 141p E 1 41000000000000n lt Back Cancel Help PSpice Advanced Analysis Users Guide 237 Chapter 7 Parametric Plotter Product Version 10 5 8 Inthe Plot Information tab right click in the plot information row and then click Display Plot This displays the trace that you plot
187. me as Reference data points only gear for cases where oe Reference only gear In this case the Advanced Analysis Optimizer tries to fit in the simulation curve to the curve specified by the reference waveform and the goal is to minimize the PSpice Advanced Analysis Users Guide 95 Chapter 4 96 Optimizer Product Version 10 5 RMS orror RMS e below the tolerance level specified by the user The error is calculated only at the reference data points Therefore X will only contain the points on the reference waveform The error calculation formula is same as used in the Weighted reference gear except that W is zero for all data points that are not on the reference waveform Simulation also gear In this case the Advanced Analysis Optimizer considers a union of the reference data points as well as simulation data points in the common interval of Time or frequency values Therefore the error is calculated using the following formula IY R S E 100x i i JR Note Notice that if W is equal to 1 for all X then the Weighted reference gear is same as the Simulation and reference data points alike gear Example Consider a situation in which the reference sweep or the value of X for the reference waveform ranges from 30u to 110u The value of X for the simulation waveform ranges from Ou to 100u In this case sweep value for error calculation Xi will range from 30u to 100u This is so because the common in
188. measured and target value Or PSpice Advanced Analysis Users Guide Product Version 10 5 Random engine Random engine Q Select the Minimize option button to reduce a value to the smallest possible value If your optimization problem is to maximize a single goal then set up the specification to minimize the negative of the value For example To maximize gain set up the problem to minimize gain When you use the LSQ or Modified LSQ engines it is sometimes difficult to determine where your starting points for optimization should be The Random engine provides a good way to find these points The Random engine applies a grid to the design space and randomly runs analysis at the grid points It keeps track of the grid points already run so that it never runs a duplicate set of parameter values Once it finishes its initial analysis it reruns the best points so you can easily use them for LSQ or Modified LSQ PSpice Advanced Analysis Users Guide 287 Chapter 9 Optimization Engines Product Version 10 5 Configuring the Random Engine The Random Engine defaults are listed in a dialog box available from the Optimizer tab s Engine Random options Profile Settings XJ ptimizer Monte Carlo Smoke Simulation Enaine s The Random Engine randomly fi 0 pud et Max Number of Runs 30 fo fo Steps per Range specified range Replay Best N Runs at End Random Number Generator Seed Curve Fit
189. measurement in a prb file local to the design 5 Click OK The Edit New Measurement dialog box appears Edit Hew Measurement oint7O7 1 y1 e 5 marked point HDesc t Find the 707 value of the trace XPression HArg1H Mame of trace to search comments 1Search forward level 70 72 5 search function 6 Typein the marked expression point707 1 y1 7 Type in the search function 256 PSpice Advanced Analysis Users Guide Product Version 10 5 For power users 1 Search forward level 70 7 p j Note The search function is enclosed within curly braces Always place a semi colon at the end of the last search function 8 Typein any explanatory comments you want Desc Find the 707 value of the trace Arg1 Name of trace to search Note For syntax information see Measurement definition syntax on page 257 Using the new measurement definition Your new measurement definition is now listed in the Measurements dialog box For an example of using a definition in a measurement expression to evaluate a trace see Example on page 242 Measurement definition syntax Check out the existing measurement definitions in PSpice for syntax examples 1 Fromthe Trace menu choose Measurements The Measurement dialog box appears PSpice Advanced Analysis Users Guide 257 Chapter 8 Measurement Expressions Product Version 10 5 2 Highlight any example and select View to
190. mizing signal shaping circuits where the circuit waveform must match the reference waveform To use curve fitting for optimizing a design you need to specify the following in the Curve Fit tab of the Advanced Analysis Optimizer 1 Acurve fit specification You can either import a specification from an existing opt file or can create a new specification Creating a new specification includes specifying a trace expression a reference file containing measured points and the corresponding measurement values and a reference waveform To know the details about the New Trace Expression dialog box see Advanced Analysis Online Help To see the detailed procedure for creating a new curve fit specification see Creating a Curve fit Specification on page 89 To know more about the reference files see Reference file on page 90 2 List of parameters to be changed All the optimizable parameters in a circuit are listed in the property map file This file is created when you netlist the design and has information of each of the device used in the circuit design Creating a Curve fit Specification 1 Specify the Trace Expression a In the Specifications area click the row stating Click here to enter a curve fit specification PSpice Advanced Analysis Users Guide 89 Chapter 4 Optimizer Reference file 90 Product Version 10 5 b In the New Trace Expression dialog box select the simulation profile from the Pro
191. n asterix symbol will be displayed along with the derate file name Smoke Smoke tran sim Derating File test drt ls Derating Max Derating caution When you select a new derate file to be used for the smoke analysis the contents of the Derating column are updated with the new values only when you rerun the smoke analysis Till you run the smoke analysis again the values displayed in the Derating column will be from the derate file used in the previous run Reading values from the derate file To be able to use the custom derate file add the DERATE_TYPE property on the design instance The value PSpice Advanced Analysis Users Guide 167 Chapter 5 168 Smoke Product Version 10 5 assigned to the DERATE_TYPE property should match the Derate Type specified by you in the derate file Consider a sample derate file sample drt This derate file has two derate types for RES category and one for capacitor To use this derate file during the smoke analysis load this file in Advanced Analysis See Adding the custom derating file to your design on page 165 Before you can use the derate file successfully you need to complete the following steps in Capture 1 Select the capacitor C1 and right click 2 From the pop up menu select Edit properties 3 Inthe Property Editor window click the New Row button 4 In the Add New Row dialog box specify the name of the new property as DERATE_TYPE PSpice
192. n the Specifications table A black arrow appears in the left column on the Specifications table the row is highlighted and the Min and Max columns display the worst case minimum and maximum measurement values The Parameters table will display the values for parameters and measurements using the selected measurement only Interpreting min and max Values displayed in the min and max columns are the parameter values at the measurement s worst case minimum and maximum values If a measurement value is insensitive to a component the sensitivity displayed for that component will be zero In such cases values displayed in the Min and Max columns will be same and will be equal to the Original value of the component Negative and positive sensitivity If the absolute or the relative sensitivity is negative it implies that for one unit positive increase in the parameter value the measurement value increases in the negative direction For example if for a unit increase in the parameter value the measurement value decreases the component exhibits negative sensitivity It can also be that for a unit decrease in the parameter value there is an increase in the measurement value On the other hand positive sensitivity implies that for a unit increase in the component value there is an increase in the measurement value 48 PSpice Advanced Analysis Users Guide Product Version 10 5 Sensitivity procedure Changing from
193. nalysis P xj Smoke Select derating type p APSpice sample sample drt Y Create a list of custom derating files Type or browse to specify the full path of your custom file Files entered below will be added to the list of available derating types Custom Derating Files pice sample sample drt Spice sample test drt To add one or more files to the Custom Derating Files list box click the New Insert button Browse and select the custom derating file The custom derating filename gets added in the Custom Derating Files list box In the Select derating type drop down list select the name of the derate file that you want to use during the smoke analysis Click OK Click the Run button blue triangle The Smoke data display title changes to 5moke profile name custom derate file name Smoke results appear after the analysis in complete The value of derate factors specified by you appear in the Derating column PSpice Advanced Analysis Users Guide Product Version 10 5 For power users Note If the active derate file is different from the derate file used for the smoke results displayed an asterix symbol will be displayed along with the derate file name Consider an example where sample drt was used to acheive the displayed smoke results 250m In this case if you change the active derate file to test drt or if you edit the existing sample drt a
194. nalysis Users Guide 231 Chapter 7 Parametric Plotter Product Version 10 5 As Parametric Plotter starts running the Output window is populated with the total number of sweeps required to complete the analysis 7 Measurements E Results Erio Information Measurements Measurement Min Value Max Value transient sim transient sim Click here to import a measurement createc Parametric Plo Processing analysis specifications Number of parametric sweeps 414 Loading simulation profile transient sim Parametric sweep run 1 Parametric sweep run 2 Once the analysis is over the Min value and the Max Value columns are populated for each measurement specified in the 232 PSpice Advanced Analysis Users Guide Product Version 10 5 Example Measurements tab Besides this results of each run of Parametric Plotter are displayed in the Results tab 7 Measurements i Results Fr Pict Information Results el walue 1e 010 0 0321775477176 1e 010 0 0324279773713 1e 010 i 0 0603237567281 1e 010 0 06554780049446 1e 010 0 08955525820374 1e 010 l 0 08928913342263 1e 010 0 0308821876144 1e 010 i 0 03261846159308 1e 010 l 0 05919543114364 1e 010 0 06712229020074 1e 010 0 08948388197998 1e 010 0 08914627690525 1e nin AAAnNAN R3 Figure 7 7 Results tab in Parametric Plotter In the Results tab you can sort and lock the results displayed in various columns For exam
195. nced Analysis Users Guide 25 Chapter 2 26 Libraries Product Version 10 5 For example in Capture s property editor a resistor could provide the following information Property Value DIST FLAT Optimizable parameters Optimizable parameters are any characteristics of a model that you can vary during simulations In order to include a circuit component in an Optimizer analysis the component must have optimizable parameters Use the Advanced Analysis library list to identify components with optimizable parameters For example in Capture s property editor an opamp could provide the following gain bandwidth Property Value GBW 1e7 Note that the parameter is available for optimization only if you add it as a property on the schematic instance and assign it a value During Optimization the GBW can be varied between any user defined limits to achieve the desired specification Smoke parameters Smoke parameters are maximum operating conditions for the component To perform a Smoke analysis on a component define the smoke parameters for that component You can still use non smoke defined components in your design but the smoke test ignores these components Use the online Advanced Analysis library list to identify components with smoke parameters PSpice Advanced Analysis Users Guide Product Version 10 5 Using Advanced Analysis libraries Most of the analog components in the standard PSpice libraries also
196. nd the location of the reference file b For each of the Trace expression specify the reference waveform tolerance and weight Select the Optimizer engine You can use either the Least Squares Quadratic Modified Least Squares Quadratic or Random engines for optimization The Discrete engine should be used after optimization to convert optimization parameters into discrete values only Start the analysis from the Optimizer Analyze or review the data in the Optimizer and refine the circuit design PSpice Advanced Analysis Users Guide 81 Chapter 4 Optimizer Product Version 10 5 8 Save and print out your results Setting up in the circuit in the schematic editor 82 Start with a circuit in Capture The circuit simulations and measurements should be already defined The simulation can be a Time Domain transient a DC Sweep or an AC Sweep Noise analysis 1 From your schematic editor open your circuit 2 Simulate the circuit 3 Check your key waveforms in PSpice and make sure they are what you expect Test your measurements and make sure they have the results you expect For information on circuit layout and simulation setup see your schematic editor or PSpice AMS user guides For information on setting up measurements see Measurement Expressions PSpice Advanced Analysis Users Guide Product Version 10 5 Optimizer procedure overview Setting up Optimizer in Advanced Analysis Setti
197. ndow of PSpice A D are available in the Import Measurements dialog box Adding new measurements 1 Inthe Measurements tab right click and select Create New Measurements The New Measurement dialog box appears 2 Fromthe Profile drop down list select the simulation profile for which you want to create the measurement 3 From the Measurements drop down list select the Measurement that you want to evaluate PSpice Advanced Analysis Users Guide 219 Chapter 7 Parametric Plotter Adding a trace Product Version 10 5 From the Simulation Output Variables list specify the variable on which the measurement is to be performed and click OK The new measurement gets added to the Measurements tab a Important Using the New Measurements dialog box you can only add the already defined measurements to the Parametric Plotter window To define new measurements in PSpice use the Trace gt Measurements command in PSpice A D Using the Parametric Plotter you can evaluate the influence of changing parameter values on a trace To be able to do this you need to add a trace in the Measurements tab 1 From the Analysis drop down menu select Parametric Plotter gt Create New Trace Alternatively right click on the Measurements tab and select Create New Trace The New Trace Expression dialog box appears Create an expression to define the new trace and click OK The trace expression gets added in the Measurement window w
198. ng up the Optimizer consists of the following tasks Opening Optimizer in Advanced Analysis Selecting an engine Defining Optimization parameters Selecting Component Parameters Setting up circuit measurements or specifications Specifying optimization goals Optimization goals are design specifications that you want to meet Therefore while defining optimization parameters you need to determine parameters that affect your goals the most Opening Optimizer in Advanced Analysis Selecting an engine From the PSpice menu in your schematic editor select Advanced Analysis Optimizer The Advanced Analysis Optimizer tool opens Optimizer in advanced analysis supports multiple engines These are Least Square LSQ Modified LSQ MLSQ Random and Discrete engines In an optimization cycle a combination of these engines is used Use these Optimizer engines for these reasons Modified LSQ engine to rapidly converge on an optimum solution LSQ engine to converge on an optimum solution if the Modified LSQ engine did not get close enough Random engine to pick a starting point that avoids getting stuck in local minima when there is a problem converging See Local and global minimums on page 270 PSpice Advanced Analysis Users Guide 83 Chapter 4 Optimizer Product Version 10 5 m Discrete engine to pick commercially available component values and run the simulation one more time with the selected commercial
199. ns Skip the initial transient bias point calculation SKIPBP 1 Click jp on the top toolbar to run the PSpice simulation 2 Review the results rf amp SCHEMATICT Tran dat active i 8s 2us U in U load The key waveforms in PSpice are what we expected From the PSpice menu in your schematic editor select Advanced Analysis Smoke PSpice Advanced Analysis Users Guide Product Version 10 5 Viewing Smoke results Example The Smoke tool opens and automatically runs on the active transient profile rf_amp SCHEMATIC1 PSpice Advanced Analysis Smoke B Ele Edit view Run Analysis Window Help 8 je m exe lft anpschenatctuensm zonam amp amp S Fe Smoke rf_amp schematic1 tran sim Ho Derating Component Parameter Type Max Derating E Starting Smoke Analysis m Performing Smoke Analysis on profile rf_amp schematic1 tran sim Smoke Analysis succeeded Smoke Analysis finished For Help press F1 mu Smoke calculates safe operating limits using component parameter maximum operating conditions and derating factors The output window displays status messages 1 Right click and from the pop up menu select Average RMS and Peak Values m RMS Values Average Values Click to choose average RMS and peak values m Peak Values Temperature Parameters Only Parameter Descript
200. ntions Our documentation uses a few special symbols and conventions Notation Bold text Icon graphic 10 Examples Description Import Measurements Indicates that text is a menu Modified LSQ or button command dialog PDF Graph box option column or graph label or drop down list option wa Gl b Shows the toolbar icon that should be clicked with your mouse button to accomplish a task PSpice Advanced Analysis Users Guide Product Version 10 5 Related documentation Lowercase file aap sim drt Indicates a file name extensions extension Related documentation In addition to this guide you can find technical product information in the embedded AutoHelp in related online documentation and on our technical website The table below describes the type of technical documentation provided with Advanced Analysis This documentation component Provides this This guide A comprehensive guide for understanding and PSpice Advanced Analysis User s using the features available in Advanced Analysis Guide PSpice Advanced Analysis Users Guide 11 Chapter Before you begin This documentation component Help system automatic and manual PSpice User s Guide PSpice Library List PSpice Reference Guide PSpice Quick Reference OrCAD Capture User s Guide 12 Product Version 10 5 Provides this Provides comprehensive information for understanding the features in Advanced Analysis and using them
201. o Optimizer Review the results of the Sensitivity calculations We need to use engineering judgment to select the sensitive components to optimize Bm We won t change R5 or R9 because they control the input and output impedances m We wont change R2 or R3 because they control transistor biasing The linear bar graph at the Relative Sensitivity setting shows that R4 R6 and R8 are also critical parameters We ll import these parameters and values to Optimizer 1 Inthe Parameters table hold down the Ctrl key and select R4 R6 and R8 64 PSpice Advanced Analysis Users Guide Product Version 10 5 Sensitivity procedure 2 Right click the selected components A pop up menu appears Send To Optimizer db Cut EBS ri Dacke ey RASCE z Delete 3 Select Send to Optimizer 4 From the View menu select Optimizer View Bun Analysis Window iy 20m Fit Biber ae Zoom Bike Zou Djs aug Select Optimizer view to switch to the Optimizer window and see the Tem parameters you sent over from Sensitivity an gt a 2 Lg Zoo Rie tT aad Optimizer becomes the active window and your critical parameters are listed in the Optimizer Parameters table Printing results Click amp Or PSpice Advanced Analysis Users Guide 65 Chapter 3 Sensitivity Product Version 10 5 From the File menu select Print Saving results Click fed Or From the File menu select Save The final results will
202. o large You might be using the wrong profile for the type of measurement you re evaluating PSpice Advanced Analysis Users Guide From the Simulation menu in PSpice choose Edit Profile to open the Simulation Settings dialog box Ensure that the data save start time in the Analysis tab is 0 Smoke analysis works only if data save start time is zero seconds Or From the Simulation menu in PSpice choose Edit Profile to open the Simulation Settings dialog box Ensure that the data collection options in the Data Collection tab is set to All for voltages currents and power Decrease the number of runs in the Monte Carlo settings tab from the Edit menu select Profile Settings and click the Monte Carlo tab Check the selected profile and change it to the profile that applies to your measurement For example change to an AC profile to evaluate bandwidth 311 Chapter 10 Troubleshooting Problem Analysis fails Possible cause Product Version 10 5 Solution Optimization didn t converge Optimization didn t converge after running through several iterations Optimization didn t converge but it looked like it was improving 312 The engine may have found a local minimum which may not be the best solution See Local and global minimums on page 270 The parameters have changed the circuit s behavior so the simulation results may not provide the information needed to meet the measur
203. on The maximum factor by which to increase the trust region This option allows you to set the maximum step size increase allowed by the LSQ engine for trial runs PSpice Advanced Analysis Users Guide 279 Chapter 9 Optimization Engines Convergence Options 280 Product Version 10 5 The following options control the convergence stopping criteria for the LSQ engine These options are similar to convergence options in PSpice Note Changes to the default values of these options can lead to an unpredictable solution minimum Use these options with extreme care Relative Function Convergence Tolerance A relative function convergence tolerance RFCTOL that checks the error size Relative convergence occurs if the Current Value Goal Values RFCTOL Current Value X Convergence Tolerance The X Convergence tolerance XCTOL that checks the step size X convergence occurs if a Newton step is tried and the relative step size is less than or equal to XCTOL Absolute Function Convergence tolerance An absolute function convergence tolerance AFCTOL AFCTOL convergence occurs if the LSQ engine finds a point where the function value half the sum of the squares is less than AFCTOL and RFCTOL and XCTOL tests have failed False Convergence Tolerance The false convergence tolerance XFTOL that checks if the solutions are converging to a noncritical point False convergence occurs if PSpice Advanced Analysis Users Guide
204. on and displays it in the Parameter Entry form PSpice Advanced Analysis Users Guide 327 Chapter A Property Files The smoke section 328 Product Version 10 5 This section of the template property file is used during the smoke analysis The main objective of a smoke analysis is to calculate the safe operating limit of all the parts used in a circuit given the Maximum Operating Conditions MOCs for each device in the circuit These MOCs are defined in the smoke section of the property file The smoke section of the template property file contains smoke parameter definitions and how to measure them for a particular device or family of devices Smoke parameters are used for defining maximum conditions that can be applied to a device The max ops desc section The max ops desc section contains the description of the smoke parameters along with the unit of measurement for the parameter All the entries in this section are displayed in the smoke parameters window in Model Editor For example IPLUS description Max input current amat nA where IPLUS smoke parameter description Max description of IPLUS input current maximum input current at the positive terminal unit A unit of measurement is Ampere The pre smoke section The pre smoke section lists default mapping between the node names and the corresponding port names in the part symbol This information is visible to you in the Test Node
205. on the graph is the restricted range Reviewing the Raw Measurements table Controlling Monte Carlo 184 The Raw Measurements table is a read only table that has a one to one relationship with the Statistical Information table For every measurement row on the Raw Measurements table there is a corresponding measurement row on the Statistical Information table The run values in the Raw Measurements table are used to calculate the yield and statistical values in the Statistical Information table 1 Click the Raw Meas tab The Raw Measurements table appears Select a row and double click the far left row header The row of data is sorted in ascending or descending order Note Copy and paste the row of data to an external program if you want to further manipulate the data Use the Edit menu or the right click pop up menu copy and paste commands From the View menu select Log File Monte Carlo to view the component parameter values for each run If you do not achieve your goals in the first Monte Carlo analysis there are several things you can do to fine tune the process PSpice Advanced Analysis Users Guide Product Version 10 5 Pausing stopping and starting Monte Carlo procedure Pausing and resuming To review preliminary results on a large number of runs Click I on the top toolbar when the output window indicates approximately Monte Carlo run 50 The analysis stops at the next interruptible point av
206. ong with the parameter types and the default values of the parameters tolerances and distributions All the parameters listed in this section are used for Sensitivity Monte Carlo and Optimizer runs All of these properties can be made available to the Optimizer provided they are added as properties on the part symbol in the schematic editor These properties can also be used for Monte Carlo analysis if they have a POSTOL and NEGTOL place holders The model_params section starts with a level entry which indicates the level of simulation parameters supported For some of the models there can be more that one level present in the property file In case of multiple level models as the parameter level goes higher the number of simulation parameters included in the model increases The highest level has all the simulation parameters of lower levels and some more simulation parameters For most of the models the level is level 0 indicating that the model is a single level model and therefore all the simulation parameters listed under level 0 are used while simulating the models If the level values are level 1 level 2 and level 3 the model is a multi level model For multi level models you can specify the simulation parameters to be used while simulating the device using the LEVEL property on the device symbol For example if you specify the value of the LEVEL property as 2 only the simulation properties listed under level 1 and lev
207. or the resistor would be 110 ohms Assuming the default value of Sv which is 40 the analysis is run with the value of the resistor set to 104 ohms 40 percent of the 10 ohm tolerance and a measurement value is obtained Using that value as a base Sensitivity assumes that the resistance change from 100 to 104 ohms is linear and calculates interpolates the measured value at 1 percent tolerance 101 ohms Worst case minimums and maximums 68 For each measurement Sensitivity sets all parameters to their tolerance limits in the direction that will increase the measurement value runs a simulation and records the measurement value Sensitivity then sets the parameters to the opposite tolerance limits and gets the resulting value If worst case measurement values are within acceptable limits for the design the measurements can in most cases be ignored for the purpose of optimization Sensitivity assumes that the measured quantity varies monotonically throughout the range of tolerances If not if there is an inflection point in the curve of output function values the tool does not detect it Symptoms of this include PSpice Advanced Analysis Users Guide Product Version 10 5 Sensitivity procedure a maximum worst case value that is less than the original value or a minimum value greater than the original value Sensitivity analysis runs Sensitivity performs the following runs m A nominal run with all parameters set at origin
208. ormation see Measurement definition syntax on page 257 Your new measurement definition is now listed in the Measurements dialog box Using the new measurement definition Your new measurement definition is now listed in the Measurements dialog box Note For steps on using a definition in a measurement expression to evaluate a trace see Composing a measurement expression on page 241 Definition example 1 From the PSpiceTrace menu choose Measurements The Measurements dialog box appears Measurements Bandwidth Bandwidth_Bandpass_3dB Bandwidth_Bandpass_3dB_ Range CenterFrequency CenterFrequency_ Range ConversionGain ConversionG ain_Range Cutoff_Highpass_3dB Cutoff_Highpass_3dB_ gt Range Cutoff_Lowpass_3dB Cutoff_Lowpass_3dB_ Range Delete DutyCycle DutyCycle XRange Falltime_NoO vershoot Falltime StepResponse Fallime StepResponse XRange GainMargin Edit Load E E Eval mn Close 2 Click New PSpice Advanced Analysis Users Guide 255 Chapter 8 Measurement Expressions Product Version 10 5 The New Measurement dialog box appears New Measurement name pointz07 r File to keep Measurement in use local file ExCadencewfamp original f amp SCHEMATIC C use global file E Cadence PSD_9 2 1 PSpice Common pspi C other file a DK Cancel Help 3 Type in a name in the New Measurement name field 4 Make sure use local file is selected This stores the new
209. orresponding categories factors and values Note Derate factors are populated based on the selected device category 10 Save the derate file Modifying existing derate file You can also use this dialog box to modify the device type device category and the associated derating factor in an existing derate file 164 PSpice Advanced Analysis Users Guide Product Version 10 5 For power users 1 Type the full path or browse to select an exisiting derate file Advanced Analysis x Smoke Select derating type p PSpice_sample sample dit Y Create a list of custom derating files Type or browse to specify the full path of your custom file Files entered below will be added to the list of available derating types 2 Click the Edit Derate File button to display the Edit Derate File dialog box Custom Derating Files Edit Derate File xi Derate File D PSpice_sample sample drt Derate Types Derate Types Device Category RES myderatetype2 r Derating Factors 0 40000000000000 0 70000000000000 Adding the custom derating file to your design To choose your custom derating file and apply the custom derating factors 1 Right click on the Smoke display PSpice Advanced Analysis Users Guide 165 Chapter 5 166 Smoke Product Version 10 5 2 From the pop up menu select Derating gt Custom Derating Files The Advanced Analysis Smoke tab dialog appears Advanced A
210. ot Falltime StepResponse Falltime StepResponse XRange GainMargin Max Max XRange Min Min XRange 248 Center frequency dB level of a waveform over a specified X range Ratio of the maximum value of the first waveform to the maximum value of the second waveform Ratio of the maximum value of the first waveform to the maximum value of the second waveform over a specified X range High pass bandwidth for the given dB level High pass bandwidth for the given dB level Low pass bandwidth for the given dB level Low pass bandwidth for the given dB level over a specified range Duty cycle of the first pulse period Duty cycle of the first pulse period over a range Falltime with no overshoot Falltime of a negative going step response curve Falltime of a negative going step response curve over a specified range Gain dB level at the first 180 degree out of phase mark Maximum value of the waveform Maximum value of the waveform within the specified range of X Minimum value of the waveform Minimum value of the waveform within the specified range of X PSpice Advanced Analysis Users Guide Product Version 10 5 Definition Finds the NthPeak Value of a waveform at its nth peak Overshoot Overshoot of a step response curve Overshoot_XRange Peak Period Period XRange PhaseMargin PowerDissipation_mW Pulsewidth Pulsewidth_XRange Q_ Bandpass Q Bandpass XRange Risetime NoO
211. p schematic ac sim mams db v load tf_amp schematicl ac sim bandwidth v load 3 rf amp schematic ac sim min 10 log10 vf inoise v inoise 8 28e 13 tf_amp schematicl ac sim mams v onoise E To select multiple items hold down the CTRL key then click each entry Hold down the SHIFT key to select or deselect adjacent items Cancel Help 3 Select the four ac sim measurements 4 Click OK The Specifications table lists the measurements Specifications Measurement Pe E emeschematici mexabeqes D A riceme schematit oendvwiettdos3 _ D fg riceme schenstict minciosogtocinoi Pe e rtaamp schematict maxcv encisey Original PSpice Advanced Analysis Users Guide 57 Chapter 3 Sensitivity Product Version 10 5 Running Sensitivity Click eon the top toolbar Senstiviy gt num Click to start 58 PSpice Advanced Analysis Users Guide Product Version 10 5 Sensitivity procedure Displaying run data Results are displayed in the Parameters and Specifications tables according to the selected measurement Parameter values that Right click to change Double click column headings to cha correspond to Display to Absolute the sort order measurement min Sensitivity Right click to change bar and max values from Linear to Log Linear 21 0667m Click to exclude from analysis 375 2423n Measurement v rf amp schematict ac sim m
212. parameter for a resistor A parameter value can be a number or a named value like a programming variable that represents a numeric value When the parameter value is a name its numerical solution can be varied within a mathematical expression and used in optimization Related to Modified LSQ optimization engine An achievable numerical value in circuit optimization A constraint is specified by the user according to the user s design specifications The Modified LSQ engine works to meet the goals subject to the specified constraints A way of displaying Monte Carlo results that shows the cumulative probability that a measurement will fall within a specified range of values The CDF graph is a stair step chart that displays the full range of calculated measurement values on the x axis The y axis displays the cumulative number of runs that were below those values A safety factor that you can add to a manufacturer s maximum operating condition MOC It is usually a percentage of the manufacturers MOC for a specific component No derating is a case where the derating factor is 100 percent Standard derating is a case where derating factors of various percents are applied to different components in the circuit See component Related to Monte Carlo When Monte Carlo randomly varies parameter values within tolerance it uses that parameter s distribution function to make a decision about which value to select See also Flat Unifor
213. parameters The Advanced Analysis libraries include components with tolerance parameters PSpice Advanced Analysis Users Guide 343 Glossary part probability distribution function PDF graph Q R Random engine relative sensitivity 344 Product Version 10 5 smoke parameters and optimizable parameters in their models See component A way of displaying Monte Carlo results that shows the probability that a measurement will fall within a specified range of values The PDF graph is a bar chart that displays the full range of calculated measurement values on the x axis The y axis displays the number of runs that met those values For example a tall bar bin on the graph indicates there is a higher probability that a circuit or component will meet the x axis values within the range of the bar if the circuit or component is manufactured and tested Related to Optimizer The Random engine uses a random number generator to try different parameter value combinations then chooses the best set of parameter values in a series of runs Relative sensitivity is the percent change in measurement value based on a one percent positive change in parameter value for the part The formula for relative sensitivity is Ms Mn 0 4 Tol Where Mn the measurement from the nominal run Ms the measurement from the sensitivity run for that parameter Tol relative tolerance of the parameter PSpice Advanced Analys
214. pcb com The max ops section in the template property file lists the default values of MOCs This information can be overridden by the information contained in the device property file Finally the smoke test section of a template property file defines the test performed and the nodes for which the test holds Example PSpice Advanced Analysis Users Guide 331 Chapter A Property Files Product Version 10 5 A section of the template property file defining the IMINUS smoke parameter is listed below IMINUS test current test term TERM NEG To test for the maximum input current at the negative terminal of OPAMP Advanced Analysis runs the current test Note The actual value of the terminal is obtained from the device pre smoke or PORT ORDER section of the corresponding DEVICE PRP file A list of valid test types and their descriptions are listed in the table below Test Name Descriptions current test Finds current in the specified terminal power test Finds power dissipation of the device temp null test voltage test Finds voltage between two nodes abs voltage test Finds absolute voltage between two nodes neg current test Finds negative current in the specified terminal breakdown test Finds breakdown voltage between two nodes abs current test Finds absolute current at the terminal 332 PSpice Advanced Analysis Users Guide Product Version 10 5 The device property file The device p
215. performance A constraint defines the performance level that the design must fulfill For example an expression indicating that the PSpice Advanced Analysis Users Guide 75 Chapter 4 Optimizer Performance 76 Product Version 10 5 output voltage that must be greater than a specific level can be a constraint The constraint specification includes Q The name of the constraint Q An acceptable range of values Q A circuit file to simulate or a simulation profile a An expression or a measurement function for measuring performance Q An allowed relationship between measured values and the target value which can be one of the following lt measured value must be less than or equal to the target value measured value must equal the target value gt measured value must be greater than or equal to the target value It is recommended that in a design nonlinear functions of the parameters should be treated as constraints and not as goals For example Bandwidth can vary as the square root of a bias current and as the reciprocal of a transistor dimension The performance of a design is a measure of how closely the calculated values of its specifications approach their target values for a given set of parameter values Each aspect of a design s performance is found by evaluating Optimizer expressionsL In many cases particularly if there are multiple conflicting specifications it is possible that the Optim
216. ph Q Select Percent Y axis to toggle from the default absolute y axis Number of Runs to Percent of Runs Change the number of bins on the x axis by going to the Edit menu selecting Profile Settings clicking the Monte Carlo tab and typing a new number in the Number of Bins text box If you want more bars on the graph specify more bins up to a maximum of the total number of runs Higher bin numbers show more detail but require more runs to be useful Working with cursors To change a cursor location on the graph click the cursor to select it and click the mouse in a new spot on the graph A selected cursor appears red The cursor s location on the graph changes and the measurement min or max values in the Statistical Information table are updated A new calculated yield displays Restricting calculation range To restrict the statistical calculations displayed in the Statistical Information table to the range of samples within the Cursor minimum and maximum range set the cursors in their new locations and select the restrict calculation range command from the right click pop up menus 1 Change cursors to new locations PSpice Advanced Analysis Users Guide 183 Chapter 6 Monte Carlo Product Version 10 5 See Working with cursors above Right click in the graph or in the Statistical Information table and select Restrict Calculation Range from the pop up menu The cross hatched range of values that appears
217. phor such as a mountain range Define the direction north south as parameter A direction east west as parameter B and the ground altitude above sea level as the total error A grid plot of the total error relative to the parameters then resembles a topographic map as the mountain range metaphor figure 270 PSpice Advanced Analysis Users Guide Product Version 10 5 LSQ engine below shows In the figure the boundaries between shading colors represent equal error values or altitude contours Local minimum Global minimum The map is bounded by the ranges of parameter A and parameter B which define your design space The terrain has mountains and valleys or regions of high or low total error Some valleys are sinks completely bounded by contours The bottom of any valley in the design space is a local minimum It may be in a sink or at a point where the valley is cut off by a design space boundary The global minimum is the lowest point within the area boundaries Ideally this point will be at sea level or zero error There is no Death Valley or negative error sink in the metaphor PSpice Advanced Analysis Users Guide 271 Chapter 9 272 Optimization Engines Product Version 10 5 Your starting point depends on the initial values of each parameter It might be close to a local minimum or on a hill overlooking several local minimums Typically your starting point will be somewhere in the middle of the design
218. ple consider that in case of the inductive switching circuit your primary goal is to restrict the power loss which is measured by yat lastx avg w r2 to less than 0 006 and then minimize the overshoot To achieve your goal first sort the values displayed in the sixth column of Figure 7 7 on page 233 To sort the values double click on the column heading The values get assorted in the ascending order Next you lock the sorted values To lock the values click the lock icon on the top of the column After sorting the power loss values sort the values displayed in the fifth column of Figure 7 7 on page 233 As a result of this sorting the values in the last column do not get disturbed As a result for all values of atlastx avg w r2 to less than 0 006 the overshoot values get sorted Thus you can view the combination s of the parameter values for which both the outputs are in the desired range PSpice Advanced Analysis Users Guide 233 Chapter 7 Parametric Plotter Product Version 10 5 Add Plot You can plot a trace between the X axis and Y axis variables for all values of a Sweep parameter by using the Plot wizard This wizard helps you specify the settings to plot a trace in the PSpice Probe window 1 Inthe Plot Information tab right click in the plot information row and then click Add Plot This displays the Plot wizard 7 Measurements 1 Results Ef Piot Information Plot Information Plot Name Pa
219. ptimization to limit how long the optimizer tries to find a solution This is done by stopping the optimizer after the maximum number of trial runs have been completed PSpice Advanced Analysis Users Guide Product Version 10 5 LSQ engine Also depending on your design the LSQ engine might find a very steep valley that it cannot descend into In this case the engine bounces from one side to the other without getting anywhere Probe the PSpice waveform analysis feature will help you prevent this situation Sensitivity Analysis Options The following options control the values used in the sensitivity analysis Note Changes to the default values of these options can lead to an unpredictable solution minimum Use these options with extreme care Sensitivity Perturbation Size The sensitivity perturbation size This controls the delta increase used to determine the parameter value in each sensitivity run The default is 0 005 which results in parameters using their present value times 0 5 percent for each sensitivity analysis Increasing the following options tends to make the algorithm take larger steps sooner The trust region is the distance that the algorithm trusts its predictions Minimum Factor to Increment Trust Region The minimum factor by which to increase the trust region This option allows you to set the minimum step size increase allowed by the LSQ engine for trial runs Maximum Factor to Increment Trust Regi
220. r PSpice Advanced Analysis Users Guide 225 Parametric Plotter Product Version 10 5 Add two voltage markers added to the circuit as shown in Figure 7 5 on page 227 are used to plot the input and the output voltages L1 Chapter 7 R4 25 v3 100vdc 12 10 2215 D 0 TR trise TF tfall Py 4u PER 10u 226 R3 V 5n l y4 di IRF640 e 10 Figure 7 4 Inductive switching circuit PARAMETER K 0 Rs 6 382m cgso 1 527n Kp 90 Vto 3 8 Rd 0 67 chd 1 5n tfall 10n trise 1 n To view the input and the output voltages you first need to simulate the circuit Simulating the circuit From the PSpice menu in Capture select Run PSpice Advanced Analysis Users Guide Product Version 10 5 Example The input and the output waveforms are displayed in Figure 7 5 The output waveform displays a spike at every falling edge of the input waveform Figure 7 5 Input waveform Spikes or Overshoots in the output waveform v U1 L1 Figure 7 6 Output Waveform Before users can use the output waveform they need to adjust the circuit components so as to reduce the overshoot within the limit acceptable to the user This can easily be done by increasing the values of resistor R3 and capacitor C1 But this results in increasing power dissipation across resistor R3 PSpice Advanced Analysis Users Guide 227 Chapter 7 228 Parametric Plot
221. r of Runs is 100 Steps per Range is 8 and you have one parameter being optimized there will be 8 trial runs However if you have 10 parameters being optimized then there will be 100 runs Replay Best N Runs at End Specifies the number of best runs the engine should rerun and display at the end of the analysis Note The Replay runs are done after the trial runs If Max Number of Runs is 100 and Replay is 10 there may be up to 110 runs total Random Number Generator Seed Specifies the seed for the random number generator Unlike the Monte Carlo tool the seed in this engine does not automatically change between runs Therefore if you rerun the Random engine without changing any values you will get the same results The Discrete engine finds the nearest commercially available value for a component The other engines calculate component values but those values might not be commercially available The discrete engine is a conceptual engine rather than a true engine in that it does not actually perform an optimization it finds available values from lists An example is a resistor that is assigned an optimal value of 1 37654328K ohms which is not a standard value Depending on the parameter tolerance and the manufacturers part number the only values available might be 1 2K and 1 5K ohms The Discrete engine selects parameter values based on discrete value tables for these parameters Once a value is selected the eng
222. r to fine tune the circuit behavior You can also use Sensitivity to identify which components affect yield the most then tighten tolerances of sensitive components and loosen tolerances of non sensitive components With this information you can evaluate yield versus cost trade offs Absolute and relative sensitivity Sensitivity displays the absolute sensitivity or the relative sensitivity of a component Absolute sensitivity is the ratio of change in a measurement value to a one unit positive change in the parameter value For example There may be a 0 1V change in voltage for a 1 Ohm change in resistance Relative sensitivity is the percentage of change in a measurement based on a one percent positive change of a component parameter value For example For each 1 percent change in resistance there may be 2 percent change in voltage Since capacitor and conductor values are much smaller than one unit of measurement Farads or Henries relative sensitivity is the more useful calculation For more on how this tool calculates sensitivity see Sensitivity calculations on page 66 Absolute sensitivity should be used when the tolerance limits are not tight or have wide enough bandwidth Where as relative sensitivity should be used when the tolerance limits are tight enough or have less bandwidth The tolerance variations are assumed to be linear in this case PSpice Advanced Analysis Users Guide Product Version 10 5 Sensitivit
223. ractice its values are limited by the system and the absolute magnitudes are usually small when a solution is near The arctan mapping function relates the normalized parameter range to the Optimizer adjusted value When the adjusted value is near zero the normalized parameter is near zero and small value adjustments produce relatively large changes in the parameter Farther from zero the same adjustments produce smaller parameter changes as shown in ranges A and B in the figure above PSpice Advanced Analysis Users Guide 275 Chapter 9 276 Optimization Engines Product Version 10 5 You define the actual parameter range by choosing minimum and maximum values The actual range is scaled and offset to the normalized range You should center the minimum and maximum values on the actual parameter starting value so that the starting value corresponds to zero in the normalized range The linear approximations in optimization algorithms work well over about 90 95 percent of the normalized parameter range Difficulties occur when the parameter approaches either of its limits When the parameter is within about one or two percent of the range from a minimum or maximum limit the slope of the mapping function approaches zero and the parameter is essentially locked at its current value When the parameter is slightly farther from a minimum or maximum limit the slope of the arctan curve changes rapidly Linear approximations cause
224. rameter Add Plot transient sim overshoot v r2 transient sim yatlastx avg Display Plot transient sim overshoot v param trise nM i rais Delete Plot 2 Select the transient sim profile and click Next Plot Information Select Profile 3 4l This wizard helps you specify the settings to plot a trace in the PSpic Probe window Y ou can plot a trace between the X axis and Y axis variables for all values of a sweep parameter Select the profile for which you want to draw a plot and click Next Back Next gt Cancel lt Back Cancel 234 PSpice Advanced Analysis Users Guide Product Version 10 5 Example 3 Select r2 value as the variable to be plotted on the X axis and click Next Plot Information Select X Axis Variable gt Select the variable to be plotted on X Axis Axis Variables c1 value param trise xe pee Note If you select a Parameter or Measurement variable to be plotted on the X axis you will only be allowed to select a Measurement variable to be plotted on the Y axis If you select Time Frequency variable the wizard will only display a list of available traces that can be plotted on the Y axis PSpice Advanced Analysis Users Guide 235 Chapter 7 236 Parametric Plotter Product Version 10 5 4 Select transient sim overshoot v 11 2 as the variable to be plotted on the Y axis and click Next Plot Infor
225. rams folder and then the Online Documentation shortcut Q From the Help menu in PSpice choose Manuals The Cadence Documentation window appears 2 Click the PSpice category to show the documents in the category 3 Double click Advanced Analysis library list to load the document into your web browser The Advanced Analysis library list contains the names of parameterized and standard libraries Most of the libraries are parameterized Standard components in the Advanced Analysis libraries are similar to standard PSpice library components Each library contains the following items m Component names and part numbers m Manufacturer names W Lists of component parameters for each component Q Tolerance parameters Q Optimizable parameters Q Smoke parameters Some component libraries primarily opamp libraries contain components with all of the parameter types PSpice Advanced Analysis Users Guide Product Version 10 5 Device Type Opamp Bipolar Transistor Analog Multiplier This library list column heading TOL TOL OPT OPT SMK SMK DIST DIST Generic Name AD101A 2N1613 AD539 With the following notation Z lt lt 2 lt 2 lt 2 lt Using Advanced Analysis libraries Examples from the library list are shown below Part Name Part Mfg Name TOL OPT SMK Library AD101A OPA Analog Y Y Y Devices 2N1613 BUN Motorola N Y Y AD539 DRI Analog N N N Devices The parameter columns ar
226. re varied In practice this assumption is not justified For some analyses especially transient analyses the goal function PSpice Advanced Analysis Users Guide Product Version 10 5 Modified LSQ engine values show discontinuous behavior for small parameter changes This can be caused by accumulation of errors in iterative simulation algorithms Glitch Measurement Parameter The hypothetical data glitch figure demonstrates a typical case The effect of the glitch is serious the optimizer can get stuck in the spurious local minimum represented by the glitch The optimizer s threshold mechanism limits the effect of unreliable data Between iterations Enter a value that defines a fraction of the current parameter value Example A Threshold value of 0 01 means that the Modified LSQ Engine will change a parameter value by 1 of its current value when the engine makes a change By default Threshold is set to 0 so that small changes in parameter values are not arbitrarily rejected To obtain good results however you may need to adjust the Threshold value When making adjustments consider the following Q If data quality is good and Threshold is greater than zero reduce the Threshold value to find more accurate parameter values PSpice Advanced Analysis Users Guide 285 Chapter 9 Optimization Engines Least squares minimization Least squares Minimization Product Version 10 5 Q If data qu
227. reference file is to be saved Click OK to generate the reference file To know the details about the Export Text Data dialog box see PSpice AD online help The reference file generated using the Export menu command has data values separated by tab The error displayed in the Error column of the Curve Fit tab is influenced by the following factors Relative Tolerance specified by the user in the Tolerance column of the Curve Fit tab Curve Fit Gear specified by the user in the Optimizer tab of the Profile Settings dialog box Curve fit gears are the methods used for error calculations Note The Profile Settings dialog box is displayed when you choose Profile settings from the Advanced Analysis Edit menu The error displayed is the difference between Root Mean Square Error Ej and the tolerance specified by the user PSpice Advanced Analysis Users Guide 93 Chapter 4 94 Optimizer Product Version 10 5 The Root Mean Square Error E ms is calculated using the following formula 2 E 100 x Nae R Si m ER Where R Y X R X Vi represents the reference value at the same sweep point and S Y X S X Y is the simulated data value X indicates the set of sweep values considered for the error calculation The value of X depends on the gear type selected by the user Legacy gear In this case each point in the reference waveform is treated as an individual specification goal by t
228. reference file contains the sweep data which is plotted on the X axis The first element in the header row indicates the type of analysis For transient analysis the entry should be Time for ac analysis it is Freq frequency For the DC analysis there is no special entry In case you leave the column header of the first column blank the Advanced Analysis Optimizer assumes the entries in the sweep column to be time or frequency depending on whether the simulation profile is ac or transient respectively The remaining entries in the header row indicate the names of the reference waveform in each column These entries are displayed in the Reference Waveform drop down list of the Curve Fit tab Creating Reference Files You can create a reference file using one of the following m Manually Write the x y points of the reference waveform in a text file Save the text file with either mdp csv or txt extension m Using the Export command in the PSpice File menu PSpice Advanced Analysis Users Guide Product Version 10 5 Error Calculation Optimizer procedure overview Load a dat file in PSpice In the PSpice File menu choose Export Select Text txt file The Export Text Data dialog box appears The Output Variable to Export list displays the list of existing traces You can add or delete traces from this list In the File name field specify the name of the reference file and the location where the
229. rm Paki the Waveform Time ame of the firs name of the second i Column 4 Frequency reference third reference E reference waveform waveform waveform Column with Sweep Data Column 0 Column 1 A sample MDP file with one reference waveform is shown below Time V D4 2 0 1 35092732941686e 022 2e 010 0 119616948068142 2 17331331036985e 010 0 129942461848259 2 51993993110955e 010 0 150499030947685 3 21319317258894e 010 0 19108946621418 4 59969965554774e 010 0 270239174365997 7 37271262146533e 010 0 420916199684143 1 14672723207623e 009 0 627191662788391 1 52335408125073e 009 0 802674531936646 2 27660777959973e 009 1 13146245479584 3 77361568603665e 009 1 87895023822784 6 76763149891049e 009 3 6644229888916 PSpice Advanced Analysis Users Guide 91 Chapter 4 92 Product Version 10 5 1 27556631246582e 008 7 35082197189331 2 46214577833191e 008 14 6913433074951 4 1200489727594e 008 24 834680557251 6 12008282819763e 008 36 7118606567383 8 12011668363586e 008 48 0069961547852 1 01201505390741e 007 58 5374412536621 1 21201843945123e 007 68 1351776123047 1 41202182499506e 007 76 6477890014648 1 61202521053888e 007 83 9403915405273 1 8120285960827e 007 89 8975143432617 2 01203198162653e 007 94 4249801635742 2 21203536717035e 007 97 4511413574219 2 41203875271417e 007 98 9281539916992 2 61204213825799e 007 98 832633972168 2 81204552380182e 007 97 1660690307617 3 01204890934564e 007 93 9547653198242 First column of the
230. roperty file A device property file lists all the models associated with a device A device property file lists the port order and maximum operating values or smoke parameter values entered by a user for a model Information in the DEVICE PRP file is divided into the device info section and the device max ops section Usually the name of a device property file indicates the device type as well For example IGBT PRP is the device property file for IGBT models based on device characteristic curves and AA IGBT PRP is the device property file for IGBT models based on PSpice provided templates A sample device property file for a parameterized or a template based model is shown below awbad201a Creator Device property file created by analog uprev on Thu Mar 1 18 48 14 IST 2001 device info MODEL TYPE 739 SYMBOL NAME 7 Pin Opamp PORT ORDER PIN model params level 1 VOS val 0 7m postol Tsm level 2 CMRR val 6 3E4 PSpice Advanced Analysis Users Guide 333 Chapter A Property Files Product Version 10 5 level 3 CINDM val lp device max ops VDIFF 30 VSMAX 40 VSMIN OQ The first line in a DEVICE PRP file is the file header or indicates the name of the model For example in the section shown above awbad201a is the model name The prefix awb in the model name indicates that it is an parameterized mo
231. rror PPE ALES Es ssm oou EE iS DES assim pavoun SS 4 jh o cikheeierteracuve tspecfcsion WX 4 SS FE EUER OM MET A me TY X For Help pr AK ER N i Column names in the v rve MU ON reference file specifications 9 ON Error Graph ON 10 Incase you want that the simulation data should be available to you even after the optimization session is complete you need to modify the Optimizer settings From Advanced Analysis the Edit menu choose Profile settings PSpice Advanced Analysis Users Guide 129 Chapter 4 Optimizer Product Version 10 5 S Le p Tip 11 12 It is recommended that you complete the steps for setting up component parameters and curve fit specifications In case you choose not to perform the steps you can use the SCHEMATIC1_complete aap file located at tools pspice tutorial capture pspic eaa bandpass bandpass PSpiceFiles SCHE MATIC1 To use the aap file provided with the design example rename SCHEMATIC1_complete aap to SCHEMATICI aap Select the Simulation tab in the Profile Settings dialog box and ensure that Optimizer data collection is set to Save All Runs Run the Optimizer The Pspice Ul comes up displayed the changes in the output waveform for each Optimizer run The Pspice UI comes up only if you have turned the dynamic viewing on After the optimization is complete you can view any of the Optimizer runs provided you had selected the Sa
232. rs Guide 197 Chapter 6 Monte Carlo Check for acceptable values compared to design specs E Statistics E Raw teas Product Version 10 5 For each Monte Carlo run Monte Carlo randomly varies parameter values within tolerance and calculates a single measurement value After all the runs are done Monte Carlo uses the run results to perform statistical analyses The following statistical results are reported for our example Mean Std Dev 3 Sigma 6 Sigma and Median In addition a yield is calculated and reported Check for acceptable Check statistical results yields near 100 Hover mouse over Clickin right corner to select Select measurement then click the flag to see profile messages Reviewing the PDF graph 198 the dotted box to edit The PDF graph is a bar chart The x axis shows the measurement values calculated for all the Monte Carlo runs The y axis shows the number of runs with measurement results between the x axis bin ranges The statistical display PSpice Advanced Analysis Users Guide Number of Runs Product Version 10 5 Example for this measurement s probability density function is shown on the PDF graph Probability Density Graph Runs 1 to 100 E 20 ue l l l SEE 21i Selectto adjust your view of the graph Mini B4 B5 Bb 87 88 89 9 391 92 93 94 95 GB SF 98 89 10 101 102 10 34 104 105 106 107 188 Max DB Load R
233. rs at the last run Simulation information for all previous simulation runs is deleted For example if the Optimizer has information stored for N number of simulation runs then select Clear Error graph history will delete all the simulation information from 0 to N 1 runs The values in the current column of the Parameters PSpice Advanced Analysis Users Guide 99 Chapter 4 Optimizer Controlling optimization 100 Product Version 10 5 window are used as the starting point for the next simulation run To get back the original parameter values you need to delete all parameters and import again Right click on the Error Graph and select Clear History from the pop up menu This removes all historical data and restores the current parameter values to last parameter value You can stop an analysis to explore optimization trends in the Error Graph reset goals when results are not what you expected or change engines Pausing stopping and starting Tostart or continue click I on the top toolbar To pause click Jf on the top toolbar The analysis pauses at an interruptible point and displays the current data To stop click Bi on the top toolbar Note Starting after pause or stop resumes the analysis from where you left off Controlling component parameters The range that Optimizer varies a component s parameter is controlled by the Max and Min values Default component values are supplied For resi
234. rt with a working circuit in the schematic editor Circuit components you want to include in the Sensitivity data need to have the tolerances of their parameters specified Circuit simulations and measurements should already be set up The simulations can be Time Domain transient DC Sweep and AC Sweep Noise analyses 44 PSpice Advanced Analysis Users Guide Product Version 10 5 Sensitivity procedure 1 Open your circuit from your schematic editor 2 Runa PSpice simulation 3 Check your key waveforms in PSpice and make sure they are what you expect 4 Checkyour measurements and make sure they have the results you expect Note For information on circuit layout and simulation setup see your schematic editor and PSpice user guides For information on components and the tolerances of their parameters see Preparing your design for Advanced Analysis on page 30 For information on setting up measurements see Procedure for creating measurement expressions on page 240 For information on testing measurements see Viewing the results of measurement evaluations on page 242 Setting up Sensitivity in Advanced Analysis 1 From the PSpice menu in your schematic editor select Advanced Analysis Sensitivity The Advanced Analysis Sensitivity tool opens Parameters Window In the Parameters window a list of component parameters appears with the parameter values listed in the Original column Only the parameters for w
235. rties are not changed then the same sequence of random numbers will be generated each time a Monte Carlo analysis is done You can use this procedure to reproduce a random simulation m Number of bins This value determines the number of divisions in the histogram A typical value is one tenth of the number of runs The minimum value is one and the maximum value is determined by the amount of available memory It is recommended that this value be less than 10 000 Running Monte Carlo Monte Carlo calculates a nominal value for each measurement using the original parameter values After the nominal runs Monte Carlo randomly calculates the value of each variable parameter based on its tolerance and a flat uniform distribution function For each profile Monte Carlo uses the calculated parameter values evaluates the measurements and saves the measurement values Monte Carlo repeats the calculations for the specified number of runs then calculates and displays statistical data for each measurement PSpice Advanced Analysis Users Guide 179 Chapter 6 Monte Carlo Controlling MonteCarlo run Product Version 10 5 For more detail on the displayed statistical data see Example s section Reviewing Monte Carlo data on page 180 The MonteCarlo analysis can only be run if tolerances are specified for the component parameters In case you want to prevent running these analysis on a component you can do so by using the TO
236. rval r Output File Options Include detailed bias point information for nonlinear controlled sources and semiconductors OP Cancel Apply Help 1 Click to run a PSpice simulation 2 Review the results The waveforms in PSpice are what we expected tf_amp SCHEMATIC1 ac dat active 5 8nUT u onoise 18KHz 188KHz 1 MHZ 18HHz 188HHz 1 8GHZ Noise Figure Frequency 190 PSpice Advanced Analysis Users Guide Product Version 10 5 Example The measurements in PSpice give the results we expected Evaluate Measurement 1 Ww ___ max dbtv load 9 41807 In PSpice View L m bandwidth 1505787meg Measurement P lb min 1 O log1 O v inoise v inoise 8 28 Results L mw l maxtvtonoise Setting up Monte Carlo in Advanced Analysis Opening Monte Carlo From the schematic editor PSpice menu select Advanced Analysis Monte Carlo PSpice Advanced Analysis Users Guide 191 Chapter 6 Monte Carlo Product Version 10 5 PDF CDF graph Raw Measurements tab Statistics tab Statistical Information table Click to import more measurements The Advanced Analysis Monte Carlo tool opens zs rf amp SCHEMATICI PSpice Advanced Analysis Monte Carlo E He Edt view Run Analysis Window Help lal xi m see Cd 88 e Probability Density Graph 2 EE S E 2 E D 0 05 0 1 0 15 0 2 0 25
237. s For example For a given design the gain shall be 20 dB 1dB for a given design the 3 dB bandwidth shall be 1 kHz for a given design the rise time must be less than 1 usec PSpice Advanced Analysis Users Guide Product Version 10 5 Goal Constraint Terms you need to understand A design must a ways have at least one goal You can have any number of goals and constraints in any combination but it is recommended that the number of goals should be less You can easily change a goal to a constraint and vice versa The Advanced Analysis Optimizer can have two types of specifications internal and external Internal specifications An internal specification is composed of goals and constraints that are defined in terms of target values and ranges These specifications are entered using the Standard tab of the Advanced Analysis Optimizer External specifications An external specification is composed of measurement data defined in an external data file which is read by the Advanced Analysis Optimizer The external specifications are entered using the Curve Fit tab of the Advanced Analysis Optimizer A goal defines the performance level that the design should attempt to meet for instance minimum power consumption A goal specification includes Q The name of the goal An acceptable range of values a Q Acircuit file to simulate a simulation profile a An expression or a measurement function for measuring
238. s The Parametric Plotter gives users the flexibility of sweeping multiple parameters It also provides a nice and an efficient way to analyze sweep results Using Parametric Plotter you PSpice Advanced Analysis Users Guide 211 Chapter 7 Parametric Plotter Product Version 10 5 can sweep any number of design and model parameters in any combinations and view results in PPlot Probe in tabular or plot form Using the Parametric Plotter you can Sweep multiple parameters Allow device model parameters to be swept Display sweep results in spreadsheet format Plot measurement results in Probe Ul Post analysis measurement evaluation Launching Parametric Plotter From Capture From the PSpice menu in Capture select Advanced Analysis gt Parametric Plot The Parametric Plotter window appears From the Start menu choose Programs gt OrCAD 10 X gt Advanced Analysis Open the aap file From the Analysis drop down list select Parametric Plotter The Parametric Plotter window appears You can now use the Parametric Plotter to analyze your circuit Using Parametric Plotter is a two steps process Stand Alone 1 3 1 212 In the first step you select the parameters to be swept and also specify the sweep type See Sweep Types on page 213 PSpice Advanced Analysis Users Guide Product Version 10 5 Sweep Types Discrete Sweep Sweep Types 2 In the second step you specify the measurements to
239. screte engine determines a new value for this resistor depending on the table used For a one percent table the new value is 2 21K The Optimizer in Advanced Analysis provides discrete value defaults for resistors capacitors and inductors 136 PSpice Advanced Analysis Users Guide Smoke In this chapter Smoke overview on page 137 Smoke strategy on page 138 Smoke procedure on page 139 Example on page 144 For power users on page 154 Smoke overview Note Smoke analysis is available with the following products O PSpice Smoke Option O PSpice Advanced Analysis Long term circuit reliability Smoke warns of component stress due to power dissipation increase in junction temperature secondary breakdowns or violations of voltage current limits Over time these stressed components could cause circuit failure PSpice Advanced Analysis Users Guide 137 Chapter 5 Smoke Smoke strategy Plan ahead 138 Product Version 10 5 Smoke uses Maximum Operating Conditions MOGs supplied by vendors and derating factors supplied by designers to calculate the Safe Operating Limits SOLs of a component s parameters Smoke then compares circuit simulation results to the component s safe operating limits If the circuit simulation exceeds the safe operating limits Smoke identifies the problem parameters Use Smoke for Displaying Average RMS or Peak values from simulation results and comparing these values ag
240. ser guides 80 Product Version 10 5 Advanced Analysis Run Sensitivity to spot the components most critical to the output optional Set up parameters you want to vary Import measurements Specify goals for the measurements Weight the goals or constraints Choose one of four engines Run Optimizer Does the design meet requirements Refine the Optimization Update the schematic with new values Print the results Save the results PSpice Advanced Analysis Users Guide Product Version 10 5 Optimizer procedure overview To obtain meaningful optimization results the Optimizer requires a problem description that consists of a circuit design a list of optimization parameters number of problem constraints derived from the design specification and a set of performance goals to optimize To optimize a circuit 1 2 3 Create or edit a circuit using Capture Simulate and define circuit measurements Determine and set up optimization parameters that you want to vary during optimization You can set up parameters from the Optimizer or on the schematic Specify the optimization specification For Internal specifications use the standard tab a Define the goal for the circuit measurements You can define goals such as rise time phase margin or entire response curves b Weight goals as needed For External specifications use the Curve Fit tab a Specify the trace expression a
241. sor turns red then click the mouse in the spot you want The new value will display in the Cursor Min or Cursor Max column in the Statistical Information table To add a new measurement click on the row that reads Click here to import a measurement Note For instructions on setting up new measurements see Procedure for creating measurement expressions on page 240 To export a new measurement to Optimizer or Monte Carlo select the measurement and right click on the row containing the text Click here to import a measurement created within PSpice Select Send To from the pop up menu Click amp b Or From the File menu select Print PSpice Advanced Analysis Users Guide Product Version 10 5 Monte Carlo procedure To print information from the Raw Measurements table on the Raw Meas tab copy and paste to an external program and print from that program You can also print the Monte Carlo Log File which contains more detail about measurement parameters From the View menu select Log File Monte Carlo Saving results Click fed Or From the File menu select Save The final results will be saved in the Advanced Analysis profile aap PSpice Advanced Analysis Users Guide 187 Chapter 6 Monte Carlo Example Product Version 10 5 This example uses the tutorial version of RFAmp located at lt target directory gt PSpice tutorial capture pspiceaa rfamp The circuit is an RF amplifier w
242. stead of simulation output variables v 4 ic Q1 Multiple point functions such as d s AVG RMS MIN and MAX cannot be used Complex functions such as M P R IMG and G cannot be used One additional function called MPAVG can also be used It is used to find the average Y value between 2 marked points The format is MPAVG p1 p2 lt fraction gt where p1 and p2 are marked X points and fraction expressed in decimal form specifies the range The range specified by lt fraction gt is centered on the midpoint of the total range The default value is 1 Example The marked point expression MPAVG x1 x5 2 will find the halfway point between x1 and x5 and will calculate the average Y value based on the 20 percent of the range that is centered on the halfway point search direction start_point consecutive_points range x range y for repeat condition 260 Brackets indicate optional arguments You can use uppercase or lowercase characters because searches are case independent PSpice Advanced Analysis Users Guide Product Version 10 5 For power users direction forward or backward The direction of the search Search commands can specify either a forward or reverse direction The search begins at the origin of the curve Forward searches in the normal X expression direction which may appear as backwards on the plot if the X axis has been reverse
243. stor VARISTOR Varistor DIODE BRIDE Half Wave and Full Wave Rectifier OCNN OCNPN Octo Coupler using NPN transistor THYRISTOR Thyristor SCR Silicon Controlled Rectifier VSRC Voltage Source C REG DIODE Current Regulator Diode POS REG Positive Voltage Regulator LED Light Emitting Diode LASER Laser DUALNPN Dual NPN Transistor DUALPNP Dual PNP Transistor DUALNMOS Dual NMOS DUALPMOS Dual PMOS 330 PSpice Advanced Analysis Users Guide Product Version 10 5 Template property file Table A 2 Supported derate type DERATE_TYPE Part NPN_PNP NPN and PNP transistors fabricated together NMOS_PMOS NMOS and PMOS fabricated together Using DERATE_TYPE the derating factor is read from the STANDARD DRT file This file lists the default derating factor for all the smoke parameters for a particular device Derating factor is the safety factor that you can add to a manufacturer s maximum operating condition MOC It is usually a percentage of the manufacturer s MOC for a specific component MOCs the derating factor and Safe Operating Limits SOL are connected by the following equation MOC x deratingfactor SOL You can also create you own derate file You can use the CUSTOM DERATING TEMPLATE DRT file as the template for creating new derate files siz Q Tip To find out how to create custom derating files see the technical note titled Creating Custom Derating Files for Advanced Analysis Smoke on www orcad
244. stors capacitors and inductors the default range is one decade in either direction PSpice Advanced Analysis Users Guide Product Version 10 5 Optimizer procedure overview For more efficient optimization tighten up the range between the Min and Max values B To change the minimum or maximum value a parameter is varied click in the Min or Max column in the Parameters table and type in the change B To use the original parameter value with no change during the next optimizing run click 4 in the Parameters table to toggle the check mark off W To lock in the current value with no change of a parameter for the next optimizing run click on the lock icon in the Parameters table to toggle the lock closed Note If you cannot edit a value and this is not the first run you may be viewing historical data To return to current data click to the right of the horizontal arrow in the PSpice Advanced Analysis Users Guide 101 Chapter 4 102 Optimizer Product Version 10 5 Error Graph Click to remove the check mark which tells Optimizer to use the Original value without variation during the next optimizing run rile re wu Ee a e fee VALUE piel ere n X0 vae y Click to lock in th current value Click a Min or Max value to type in a change without variation Default component values are supplied during the next For resistors capacitors and inductors the default range is one de
245. sults Saving results Try a different component for the circuit Or Change the tolerance of a parameter on an existing component Rerun the PSpice AMS simulation and verify that the results are what you expect Rerun Monte Carlo using the settings saved from the prior analysis Review the results Click amp Or From the File menu select Print To print information from the Raw Measurements table on the Raw Meas tab copy and paste to an external program and print from that program You can also print the Monte Carlo Log File which contains more detail about measurement parameters Click dl Or PSpice Advanced Analysis Users Guide 209 Chapter 6 Monte Carlo Product Version 10 5 From the File menu select Save The final results will be saved in the Advanced Analysis profile aap 210 PSpice Advanced Analysis Users Guide Parametric Plotter In this chapter Overview on page 211 Launching Parametric Plotter on page 212 Sweep Types on page 213 Specifying measurements on page 218 Running Parametric Plotter on page 220 Viewing results on page 221 Example on page 225 Overview Note Parametric Plotter is available only if you have PSpice Advanced Analysis license The Parametric Plotter added to Advanced Analysis provides you with the functionality of sweeping multiple parameters Once you have created and simulated a circuit you can use the Parametric Plotter to perform this analysi
246. surements in PSpice give the results we expected PSpice Advanced Analysis Users Guide 55 Chapter 3 Sensitivity Product Version 10 5 Setting up Sensitivity in Advanced Analysis 1 From the PSpice menu in your schematic editor select Advanced Analysis Sensitivity The Advanced Analysis window opens and the Sensitivity tool is activated Sensitivity automatically lists component parameters for which tolerances are specified and the component parameter original nominal values Sensitivity Parameters table prior to the first run i rf amp SCHEMATICI PSpice Advanced Analysis Sensitivity JB File Edit view Run Analysis Window Help s A amp X e sese z Parameters Linear Specifications For Help press F1 F 7 Sensitivity Specifications table before a project is set up and run 56 PSpice Advanced Analysis Users Guide Product Version 10 5 Sensitivity procedure In case you want to remove some parameters from the Parameters list you can do so by modifying the parameter properties in the schematic capture tool 2 Inthe Specifications table right click the row titled Click here to import a measurement created within PSpice The Import Measurement s dialog box appears with measurements configured earlier in PSpice x Import Measurement s Profle Measurement rf amp schematicl tran sim lt No measurements found for this profile gt rf am
247. t 2 Select PSpice gt Advanced Analyses gt Import Optimizable Parameters 3 Select AMS Simulator gt Advanced Analyses gt Import Optimizable Parameters The Import Optimizable Parameters dialog box appears Note After you select the component you can right click and select Import Optimizable Parameters from the pop up menu 4 Select the parameters you want to vary and click OK The parameter name and the default value is now displayed in the schematic editor 5 Savethe schematic Exporting Device level parameters to Optimizer 1 Select the component 2 Select PSpice gt Advanced Analyses gt Export Parameters to Optimizer 3 Select AMS Simulator gt Advanced Analyses gt Export Parameters to Optimizer The component and parameters gets added in the Parameters table Note This feature of exporting device level parameters to Optimizer is available only for components based on PSpice provided templates 134 PSpice Advanced Analysis Users Guide Product Version 10 5 Optimizer log files Engine Overview Engine Overview After every optimization run Optimizer generates log files This file contains information that can be used at instances where optimization failed to converge To view the optimizer log files choose View gt Log Files gt Optimizer The Optimizer log file opens in the text editor Optimizer includes four engines Least Squares Quadratic LSQ Optimization engine The LS
248. t Mean Std Dev 3 Sigma in percent 6 Sigma in percent Median Measurement value at the cursor minimum location Measurement value at the cursor maximum location The number of runs that meet measurement specifications represented by the cursors versus the total number of runs in the analysis Used to estimate mass manufacturing production efficiency The average measurement value based on all run values See Raw Measurement table for run values Standard deviation The statistically accepted meaning for standard deviation The number of measurement run values that fall within the range of plus or minus 3 Sigma from the mean The number of measurement run values that fall within the range of plus or minus 6 Sigma from the mean The measurement value that occurs in the middle of the sorted list of run values See Raw Measurement table for run values Reviewing the PDF graph PSpice Advanced Analysis A PDF graph is a way to display a probability distribution It displays the range of measurement values along the x axis and the number of runs with those measurement values along the y axis 1 Select a measurement row in the Statistical Information table Users Guide 181 Chapter 6 Monte Carlo Reviewing the CDF graph 182 Product Version 10 5 If the PDF graph is not already displayed right click the graph and select PDF Graph from the pop up menu The corresponding PDF graph will display all measurem
249. t List text box Look for p in the lower right corner of the dialog box This is the Parameterized Part icon If this icon appears when the part name appears in the Part text box the component comes from an Advanced Analysis library Preparing your design for Advanced Analysis 30 You may use a mixture of standard and parameterized components in your design but Advanced Analysis is performed on only the parameterized components You may create a new design or use an existing design for Advanced Analysis There are several steps for making your design Advanced Analysis ready PSpice Advanced Analysis Users Guide Product Version 10 5 Preparing your design for Advanced Analysis See Modifying existing designs for Advanced Analysis on page 35 Creating new Advanced Analysis ready designs Select parameterized components from Advanced Analysis libraries 1 Openthe online Advanced Analysis library list found in Cadence Online Documentation 2 Find a component marked with a Y in the TOL OPT or SMK columns of the Advanced Analysis library list Components marked in this manner are parameterized components 3 Forthat component write down the Part Library and Part Name from the Advanced Analysis library list 4 Addthe library to your design in your schematic editor 5 Place the parameterized component on your schematic Setting a parameter value For example select the resistor component from the pspice elem A
250. tarting run number N negative sensitivity 48 NEGTOL 32 nominal value 343 normal distribution function 341 numerical conventions 20 mega 21 milli 20 O optimization 73 choosing least squares or minimization 286 constrained least squares 73 constrained minimization 73 controlling parameter perturbation 283 for one goal 286 goals 81 limiting iterations 283 procedure overview 81 unconstrained least squares 73 optimizations Advanced Analysis 71 xi RE PSpice 39 Optimizer 78 optimizer adding a new measurement 103 allowable PSpice simulations 17 analysis runs 99 clearing the Error Graph history 100 constraints 87 controlling component parameters 100 controlling optimization 100 displaying rundata 99 editing a measurement 102 excluding a measurement from analysis 102 goals 87 hiding a measurement trace 102 importing measurements 87 July 2005 overview 71 pausing a run 100 procedure 82 setting up component parameters 85 setting up in Advanced Analysis 84 setting up measurement specifications 87 88 setting up specifications 87 setting up the circuit 82 starting a run 99 100 stopping a run 100 strategy 83 weighting the goals or constraints 88 workflow 80 Optimizer expression 78 options Delta 283 Least Squares 286 Max Iterations 283 Minimize 287 original value 343 output variables selecting 241 P parameter 24 74 parameterized components 24 parameterized library 343 Parameterized Part icon 30 p
251. te Raw measurement tab is not selected Bin size is too small for desired detail None needed This is normal behavior In the Error Graph click on the Nth end run s vertical line Current results will appear in the Parameters table In the Optimizer Parameters table click the icon for the applicable parameter This will close the lock and the parameter value will not change for subsequent runs Create a discrete values table for your non RLC component using instructions provided in Adding User Defined Discrete Table on page 132 Change the Optimizer engine to Discrete in the drop down list Click on the tab labeled Raw Meas to bring individual run results to the foreground on your screen Increase bin size in the Monte Carlo setting tab from the Edit menu select Profile Settings and click the Monte Carlo tab PSpice Advanced Analysis Users Guide Product Version 10 5 Problem Results are not what you expected Possible cause Common problems and solutions Solution The Monte Carlo PDF CDF graph doesn t look right for my measurement can t see the CDF graph can t find the parameter values for my Monte Carlo runs The applicable measurement row may not be highlighted Graph defaults to PDF view Monte Carlo parameter values are only available in Click on the measurement row The resulting graph corresponds to that measurement Right click the
252. ted CurrentPlot1 dat 16 transient sim ouershoot u 11 2 r2 ivalue 238 PSpice Advanced Analysis Users Guide Measurement Expressions In this chapter m Measurements overview on page 239 Measurement strategy on page 240 m Procedure for creating measurement expressions on page 240 m Example on page 242 B For power users on page 253 Measurements overview Measurement expressions evaluate the characteristics of a waveform A measurement expression is made by choosing the waveform and the waveform calculation you want to evaluate The waveform calculation is defined by a measurement definition such as rise time bandpass bandwidth minimum value and maximum value For example if you want to measure the risetime of your circuit output voltage use the following expression Risetime v out PSpice Advanced Analysis Users Guide 239 Chapter 8 Measurement Expressions Product Version 10 5 For a list of the PSpice measurement definitions see Measurement definitions included in PSpice on page 247 You can also create your own custom measurement definitions See Creating custom measurement definitions in the Power user section of this chapter Measurement strategy B Start with a circuit created in Capture and a working PSpice simulation m Decide what you want to measure m Select the measurement definition that matches the waveform characteristics you want to measure B Insert the ou
253. ter Product Version 10 5 Therefore the design challange here is to balance the power dissipation and the voltage overshooot To find an acceptable soultion to the problem we will vary the values of resistance R3 capacitor C1 and rise time of the input pulse and monitor the effect of varying the parameter values on the overshoot and the power dissipation across resistor R3 To achieve this use Parametric Plotter to run the sweep analysis Before you can run the sweep analysis complete the following sequence of steps 1 Launch Parametric Plotter 2 Add sweep parameters 3 Add measurements 4 Run sweep analysis Launch Parametric Plotter om the PSpice menu in Capture select Advanced Analysis Parametric Plot Add sweep parameters For the switching circuit design we will vary t rise linearly specify discrete values for R3 and vary C1 logarithmically 1 Inthe Sweep Parameters window click the Click here to import a parameter from the design property map row 2 In the Sweep Parameters window select the parameter namedtrise andclick inside the corresponding Sweep Type grid 3 From the drop down list select Linear 4 Tospecify the range within which the parameter values should be varied click corresponding Sweep Values grid 5 Inthe Sweep Settings dialog box specify start value as 5n Stop value as 12n and the step value as 1n PSpice Advanced Analysis Users Guide Product Version 10 5 Example
254. terval between ranges 0 100u and 30u 110u is 30u to 100u Lets assume that in the above mentioned range there are 100 reference data points and a total of 400 data points simulation plus reference on which error is being calculated The Erms will be calculated for all the 400 data points For each value of Xi Si which is the simulated value at Xi can either be an exact value specified in the simulation data dat file or itcan be the interpolated value at Xi Similarly Ri which PSpice Advanced Analysis Users Guide Product Version 10 5 Optimizer procedure overview is the reference value at Xi can either be an exact value specified in the reference file or it can be the interpolated value at Xi Thus for the simulation also curve fit error gear Xi contains both the reference file points and the simulation sweep points a total of 400 data points The error between the Ri and Si is calculated at each of the 400 points and the RMS of this error waveform is calculated The ratio of RMS of the error waveform and the RMS of the reference waveform R is calculated and normalized to the equivalent percentage For the weighted reference curve fit error gear the weighted RMS error is calculated at each of the 400 points Xi In this case there is one reference point for every four simulation data points assuming linear distribution of reference and simulated data points So each of the reference points is weighted by a scale f
255. the Implementation statement has all the entries in the device property file as any other device The Model Editor uses the Implementation statement to access the device specific information of the associated parts for the same model PSpice Advanced Analysis Users Guide 337 Chapter A Property Files Product Version 10 5 338 PSpice Advanced Analysis Users Guide Glossary A absolute sensitivity B bimodal distribution function The change in a measurement caused by a unit change in parameter value for example 0 1V 1Ohm The formula for absolute sensitivity is Ms Mn Pn 0 4 Tol Where Mn the measurement from the nominal run Ms the measurement from the sensitivity run for that parameter Tol relative tolerance of the parameter Related to Monte Carlo This is a type of distribution function that favors the extreme ends of the values range With this distribution function there is a higher probability that Monte Carlo will choose values from the far ends of the tolerance range when picking parameter values for analysis PSpice Advanced Analysis Users Guide 339 Glossary C component component parameter constraint cumulative distribution function CDF D derating factor device distribution function 340 Product Version 10 5 A circuit device also referred to as a part A physical characteristic of a component For example a breakdown temperature is a
256. tie Disco ui ee Pha lie as en Sone Regen A aoe a tat te dd 187 Example 253 a a iit tardius he ted quu tt dpi Reg Sd Pune Stee eae 188 Setting up the circuit in the schematic editor llle 188 Setting up Monte Carlo in Advanced Analysis 000 0c eee eee ees 191 Running Monte Carlo 3 oat E oed e ones hae eee ea REOR E Ree d etus 196 Reviewing Monte Carlo data 52v vd nera recor ODE o an cat n a OR FC Ee RC 197 Controlling Monte Carlo ure td Fes otio P roe cles eR ee eae ee bee 205 Printing Tesulls a 221 ep ek A Gron Dio ied CS ACA S oleo irs hoe oe E 209 DAVIFIOUMOSUNG uie suse ano iw 8 5 Discs bec E dun Bares Pe Ss SAL awed s dns one OWE 209 1 Parametric Plotter 211 IrnistbllSehaplet ecciesia qe qe ERE EE MEER QE TR ette aud dca ipe dede 211 OVERVIEW S sesssqimet ous b es d av und erede Deu Arousa pera D Mua iu ME e pu Eds 211 Launching Parametric Plotter osos or cate ndr gro RETE E COE SI o ecard 212 Sweep TYPES iuit atr E s Rb fo ee tea ti di Me e Are Spb e dee pt A easels wld eat eld 213 Adding sweep parameters 553 db ke EIPSERA NERA MERDA RE EELISS 216 Specifying measurements 0 cee eee eee eee eens 218 Adding measurement expressions 00 ee 219 Adding a trace sde pina an a R Ec E 220 Running Parametric Plotter 30 998 2 ve Ear arm e ei OE ro Kan goa Nea E es 220 Viewing results 42 32 tu iron oy epu Rot lee I cedet rita Da b AR RUN o ee ee rund 221 R s lts taD She A
257. to one Note Trial and error experimenting is usually the best way to select an appropriate weight Pick one weight and check the Optimizer results on the Error Graph If the results do not emphasize the weighted trace more than the rest of the traces on the graph pick a higher weight and rerun the Optimization Repeat until you get the desired results Guidelines for setting up measurement specifications Determine your requirements first then how to measure them Don t set conflicting goals For example Vout gt 5 and Vout 2 when the input is 3V Make sure enough data points are generated around the points of measurements Good resolution is required for consistent and accurate measurements Simulate only what s needed to measure your goal For example for a high frequency filter start your frequency sweep at 100 kHz instead of 1 Hz Setting up curve fit specifications Use curve fitting for following 1 To optimize a model to one or more sets of data points Using curve fitting you can optimize multiple model parameters to match the actual device characteristic represented either waveforms from data sheets or measured data PSpice Advanced Analysis Users Guide Product Version 10 5 Optimizer procedure overview 2 When the goal functions are specified as values at particular points YatX 3 To optimize circuits that need a precise AC or impulse response For example you can use curve fitting for opti
258. tput variable whose waveform you want to measure into the measurement definition to form a measurement expression B Testthe measurement expression Procedure for creating measurement expressions Setup Before you create a measurement expression to use in Advanced Analysis 1 Design a circuit in Capture 2 Setup a PSpice simulation The Advanced Analysis tools use these simulations Q Time Domain transient Q DC Sweep Q AC Sweep Noise 3 Run the circuit in PSpice 240 PSpice Advanced Analysis Users Guide Product Version 10 5 Procedure for creating measurement expressions Make sure the circuit is valid and you have the results you expect Composing a measurement expression These steps show you how to create a measurement expression in PSpice Measurement expressions created in PSpice can be imported into Sensitivity Optimizer and Monte Carlo You can also create measurements while in Sensitivity Optimizer and Monte Carlo but those measurements cannot be imported into PSpice for testing First select a measurement definition and then select output variables to measure The two combined become a measurement expression Work in the Simulation Results view in PSpice In the side toolbar click on Hl 1 Fromthe Trace menu in PSpice select Measurements The Measurements dialog box appears 2 Select the measurement definition you want to evaluate 3 Click Eval evaluate The Arguments for Measurement Eva
259. u may encounter in any of the Advanced Analysis tools Check the following tables for answers these problems m Analysis fails Results are not what you expected a B Can t make user interface do what you want a Not enough disk space or memory Possible cause Solution Smoke analysis won t run Smoke analysis won t run message says cannot find dat file 308 May not have a transient profile in the design If a transient profile is included in the design Smoke automatically picks the first transient profile for the analysis Transient analysis simulation may not be done Smoke analysis only works if you have one or more transient profiles Smoke does not work on AC or DC sweeps Simulate the transient analysis in PSpice review the waveform and measurement results then run Smoke PSpice Advanced Analysis Users Guide Product Version 10 5 Problem Analysis fails Possible cause Common problems and solutions Solution Smoke analysis fails Output window displays the following error for smoke parameters Data not found for Smoke test Please verify Save Data and Data Collection options in the simulation profile Monte Carlo analysis takes too long get an evaluation error message Data save start time is not zero or data collection options for voltages currents and power is not set to All The number of runs may be too large You might be using th
260. ubcircuit Nodes z 197 variables listed PSpice Advanced Analysis Users Guide 303 Chapter 10 Troubleshooting Product Version 10 5 A measurement that calculates the 3dB point appears in the Measurement Results table db U Load Trace 2 Evaluate Measurement Bandwidth V Load 3 gt ax db v Load 3 Click here to evalu 6 4 dB 150 50380meg Evaluation Failed P 5 42770 asurement The new measurement shows that the 3dB point of trace 2 is at 6 4 dB 3 Click mE to enable the Probe cursor tyes xrnruevv uve Pet Il SCHEMATICT AC Phy RB oR ME Y Click to activate the probe cursor Toggle cursor I 4 Activate trace 2 in the probe cursor A1 1 8888K 15 404 A2 1 8080K 12 603 dif 6 600 2 8005 ETE NT Pdp U Load Click to activate trace 2 in the Evaluate Measure probe cursor mMm mari nibii nad rm 5 Click at the left end of trace 2 The probe cursor shows that trace 2 s 3dB point 6 4dB occurs before 1kHz 304 PSpice Advanced Analysis Users Guide Product Version 10 5 Example The Optimizer is increasing the bandwidth as we asked it to in the measurement specification but not exactly in the way we wanted While this results show a slightly higher bandwidth we are more interested in increasing the cut off frequency At 1kHz the Al 1 88880K A2 951 176H dif 951 175H
261. ulated during that run Historical PSpice Advanced Analysis Users Guide 117 Chapter 4 Optimizer Product Version 10 5 run data cannot be edited It is read only as indicated by the cross hatched background Click arun line to see HEMATICI PSpice Advanced Analysis Optimizer data for that run Ele Edit view Run Analysis Window Help The data in the ze amp e optimize Mcaiiea LSQ 7 bum IR a GG Parameters and m i AA TE Run Specifications tables will change to reflect the values of that run Ru Namber To clear the Error Graph and remove all historical data right click on the Error Graph and Standard ZZ curve Ft On Off Profile Measurement Min Max Type Weight Original Current Error t B amp ac sim max db v load 5 5 5000 Constraint 20 i ac sim bandwidth v load 3 200000000 Goa 1 LZ Jac sim min 10 log1 O v inoise 5 Constraint 1 re 4 E ac sim max v onoise 3n Constraint 20 select Clear History 7 Click here to E ELLLELLLLU a measurement created within PSpice from the pop up RIEN EE nos ska Sn x Optimization run 4 Optimization run 5 C ick to remove th e Optimization complete check mark which For L pease Fi excludes the measurement fro Click the graph symbol to toggle the Cells with cross hatched the next optimization symbol of
262. um drain source voltage V Power MOSFET VGSF MOSFET or Maximum forward gate source voltage V Power MOSFET VGSR MOSFET or Maximum reverse gate source voltage V Power MOSFET ITM Varistor Peak current A 158 PSpice Advanced Analysis Users Guide Product Version 10 5 Smoke Parameter Name and Symbol Semiconductor For power users Property Name Component Maximum Operating Condition RCA Varistor Thermal resistance Case to Ambient degC W RJC Varistor Thermal resistance Junction to Case degC W TJ Varistor Maximum junction temperature degC IFS Zener Diode Maximum forward current A IRMX Zener Diode Maximum reverse current A PDM Zener Diode Maximum power dissipation W RCA Zener Diode Thermal resistance Case to Ambient degC W RJC Zener Diode Thermal resistance Junction to Case degC W TJ Zener Diode Maximum junction temperature degC The following table lists smoke parameter names for Op Amp components The table is sorted in alphabetical order according to parameter names that will display in the Smoke results Smoke Parameter Op Amp Name Component Maximum Operating Condition IPLUS OpAmp Non inverting input current IMINUS OpAmp Inverting input current IOUT OpAmp Output current VDIFF OpAmp Differential input voltage VSMAX OpAmp Supply voltage VSMIN OpAmp Minimum supply voltage VPMAX OpAmp Maximum input voltage non inverting VPMIN OpAmp Minimum input voltage non inverting PSpice Advanc
263. value is either greater than or equal to the End Value Example If for a parameter you specify the start value as 1 End value as 2 5 and the step value as 0 5 the parameter values used by the Parametric Plotter are 1 1 5 2 and 2 5 In the logarithmic octave sweep the parameters are varied as a function of 1n 2 For Logarithmic Octave sweep you need to specify the Start Value End Value and number of points per Octave Number of points per Octave is number of points between the start value and two times start value For example if the start value is 10 number of points per Octave is 5 this implies that for sweep analysis the Parametric Plotter will pick up 5 value between 10 and 20 with 20 being the fifth value During the analysis the parameter value in increased by a factor that is calculated using the following equation factor exp 1n 2 N Where N Number of points per octave PSpice Advanced Analysis Users Guide Product Version 10 5 Logarithmic decade sweep Sweep Types Example Consider that the sweep type for a parameter is LogarithmicOct The start value end value and the number of points per Octave are specified as 10 30 and 2 respectively The values used by the Parametric Plotter for LogarithmicOct sweep type will be 10 14 142 20 28 284 and 40 In this example the difference between start and end values is more than an octave therefore the actual number of values used by t
264. values that are calculated using the original values appear in the Parameters window For example in the circuit value of R4 is 1 2K Therefore the value displayed in the Original column against R4 is 1200 The min value displayed is 120 1200 10 and the max value displayed is 12000 1200 10 In the Parameters tab if you do not want the value of a particular parameter to change you can do so by locking the parameter value Lock the parameter values for R6 and R5 You can also ignore some of the parameter values Though we added the parameter R3 we will ignore it for this optimizer session To do this clear the check mark next to the message flag Setting up curve fit specification 1 2 Select the Curve Fit tab in the Optimizer window In the Curve Fittab add specifications Select the Click here to enter a curve fit specification row In the New Trace Expression dialog box first select P from the list of Analog operators and Functions and then select V out from the list of Simulation Output Variables The Measurement text box should read P V out Click OK to save the new trace expression PSpice Advanced Analysis Users Guide 127 Chapter 4 128 Optimizer Product Version 10 5 In the Reference File text box specify the location of reference txt Click the Ref Waveform list box From the drop down list that appears select PHASE Note The entries in the drop down list are the column hea
265. vanced Analysis P5pice and Schematic Editor Check last run Run Optimizer waveforms and Measurements results If applicable edit Measurements Simulation prafile Parameter values in schematic editor Review analysis Messages Select a problem spec or profile and return to Resimulate PSpice If parameter values or measurements were changed in PSpice import the new parameter values and copy and paste the new measurements into Optimizer 294 PSpice Advanced Analysis Users Guide Product Version 10 5 Procedure Procedure When an optimization analysis fails you can use the troubleshooting feature to troubleshoot a problem specification Read the error message in the output window to locate the specification to troubleshoot or look for a yellow or red flag in the first cell of a specification row 1 Right click anywhere in the specification row you want to troubleshoot A pop up menu appears 2 Select Troubleshoot in PSpice PSpice opens and the measurement specification data is displayed in the window The first trace shows the data from the run with the original schematic values The second trace shows the data from the last run 3 Right click on a trace and from the pop up menu select Information A message appears about the trace data 4 Make any needed edits Q In the PSpice window check the measurement plot or click on E to view the simulation output file Q Inthe PSpice Measur
266. ve All Runs option in the Profile Settings dialog box Viewing an Optimizer run 1 2 130 Select run 4 in the Error Graph section Select the curve fit specification for which you want to view the run Select the first specification Right click and select View Run 4 in PSpice The trace for the selected run opens in PSpice PSpice Advanced Analysis Users Guide Product Version 10 5 For Power Users For Power Users What are Discrete Tables After you have run Advanced Analysis optimizer and obtained the optimum values for your parts it is possible that those values may not be commercially available Optimizer has a Discrete engine feature that finds the closest available manufacturer s values for your parts These values are discrete values and can be selected from a drop down list of discrete values tables in Advanced Analysis Optimizer Discrete tables provided by the Advanced Analysis Optimizer are located at lt your_installation_dir gt tools pspice librar y discretetables Under this directory you find the following subdirectories that contain the discrete value tables corresponding to each part B Capacitance m Inductance m Resistance With Advanced Analysis you get six discrete values tables These tables are available on a global level The range of values for each of the discrete value table is listed below Part Discrete table alias Range of values Resistor Resistor 1 10
267. vershoot Risetime StepResponse Risetime StepResponse XRange SettlingTime SettlingTime XRange PSpice Advanced Analysis Users Guide Overshoot of a step response curve over a specified range Value of a waveform at its nth peak Period of a time domain signal Period of a time domain signal over a specified range Phase margin Total power dissipation in milli watts during the final period of time can be used to calculate total power dissipation if the first waveform is the integral of V load Width of the first pulse Width of the first pulse at a specified range Calculates Q center frequency bandwidth of a bandpass response at the specified dB point Calculates Q center frequency bandwidth of a bandpass response at the specified dB point and the specified range Risetime of a step response curve with no overshoot Risetime of a step response curve Risetime of a step response curve at a specified range Time from begin x to the time it takes a step response to settle within a specified band Time from begin x to the time it takes a step response to settle within a specified band and within a specified range Example 249 Chapter 8 Measurement Expressions Product Version 10 5 Bandwidth_Bandpass_3dB Bandwidth 3dB level of a waveform Bandwidth Bandpass 3dB XRang Bandwidth 3dB level of a waveform over e a specified X range CenterFrequency Center frequency dB level of a waveform 250
268. y distribution function 181 sensitivity bar graph 49 59 smoke bar graph 148 150 152 implementation statement 337 iterations limiting in Enhanced LSQ optimization 283 K keywords semiconductors 156 L least squares constrained 73 unconstrained 73 least squares algorithm 270 2 Least Squares option 286 Least Squares Quadratic LSQ engine 342 libraries installation location 27 library list location 28 selecting parameterized components 31 tool tip 29 using the library list 28 libraries used in examples ANALOG 33 PSPICE ELEM 36 SPECIAL 34 linear bar graph style 49 linear sweep 214 local minimum 270 342 log bar graph style 49 Logarithmic Decade sweep 21 6 Product Version 10 5 PSpice Advanced Analysis Users Guide Logarithmic Octave sweep 214 logarithmic sweep Decade 215 Octave 214 loosening LSQ engine options 278 LSQ algorithm 270 LSQ engine iterations 273 options AFCTOL 280 defaults 277 INCFAC 279 RDFCMX 279 RFCTOL 280 XCTOL 280 XFTOL 280 LSQ engine options 278 LTOL 32 M Max Iterations option 283 maximum operating conditions OCs 342 measurement disable 102 editing 102 123 exclude from analysis 102 expressions 239 hiding trace on graph 102 importing from PSpice 103 strategy 240 measurement definition selecting and evaluating 241 syntax 257 writing a new definition 255 measurement definitions creating custom definitions 253 measurement expression
269. y strategy Sensitivity strategy If Sensitivity analysis shows that the circuit is highly sensitive to a single parameter adjust component tolerances on the schematic and rerun the analysis before continuing on to Optimizer Optimizer works best when all measurements are initially close to their specification values and require only fine adjustments Plan ahead Sensitivity requires B Circuit components that are Advanced Analysis ready See Chapter 2 Libraries for more information B A circuit design that is working and can be simulated in PSpice B Measurements set up in PSpice See Procedure for creating measurement expressions on page 240 Any circuit components you want to include in the Sensitivity data need to be Advanced Analysis reagy with their tolerances specified See Chapter 2 Libraries for more information PSpice Advanced Analysis Users Guide 43 Chapter 3 Sensitivity Product Version 10 5 Workflow Schematic editor PSpice Advanced Analysis Set up or edit circuit Simulate the circuit Import Measurements Check waveforms and measurement results Change components Does design Send critical or edit tolerance meet parameters to parameter values requirements Optimizer Yes Print the results Save the results These processes are explained in your schematic editor and PSpice user quides Sensitivity procedure Setting up the circuit in the schematic editor Sta
270. ying parameter values from a previous optimization run into the current run database You can then modify optimization specifications or engine settings and run the Optimizer again to see the effects of varying certain parameters The Copy History to Next Run command allows you to copy the parameter values of the selected run to the last run which is also the starting point for the next simulation run Caution Using Copy History To Next Run you can only copy the parameter values of the selected run The specifications engine and engine settings are not copied Use the following procedure to copy history 1 Inthe Error Graph select a run that you want to copy PSpice Advanced Analysis Users Guide 103 Chapter 4 Optimizer Product Version 10 5 104 The history marker appears positioned on the selected run 2 Right click on the Error Graph 3 Select Copy History To Next Run from the pop up menu The parameters values are copied from the current marker run for example Run 1 to the end run Note The Copy History To Next Run command is available only when you stop the Optimizer Selecting Pause does not enable this menu command Consider a case where during optimization parameter values do not converge after a particular point In such cases you can stop the Optimizer copy the parameter values to the last run select a different Optimizer engine and run the optimizer again PSpice Advanced Analysis Users
271. zation Click to remove the Parameters Next Run check mark which Component Parameter Curr tells Optimizer to SA ae Doty ite e ire vae oie lye n vae j ae EM 1L Click here to import a parama er from the oo bl map use the Original value without variation during the next optimizing run Click to lock in the current value Click a Min or Max value to type in a change without variation Default component values are supplied during the next For resistors capacitors and inductors the default range is one decade optimizing run in either direction Setting up measurement specifications Measurements set up earlier in PSpice specify the circuit behavior we want to optimize The measurement specifications set the min and max limits of acceptable behavior When using the Modified LSQ engine you can also weigh the importance of the measurement specifications and mark them as constraints or goals The engine strives to get as close as possible to the goals while ensuring that the constraints are met When there is more than one measurement specification change the number in the weight column if you want to emphasize the importance of one specification with respect to another PSpice Advanced Analysis Users Guide 113 Chapter 4 Optimizer Product Version 10 5 1 Inthe Specifications table click on the row containing the text Click here to import Es SCHEMATICI PSpice Adv

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