PSPICE (w/ Capture) Primer - SEAS
Contents
1. Reading and checking circuit Circuit read in and checked no errors DC Analysis DC Analysis finished Simulation complete For Help press F1 Figure 8 Probe window 100 SS SRaee Se 1 From the TRACE menu select ADD TRACE and select the voltages and current you like to display In our case we ll add V out and V in Click OK oo Add Traces E Funchons or Macros Analog Operators and Functions Simulation Output Yarnables IY Analog Digital IY Voltages M Currents I Power Moise Meel M Alias Names Subeireuit Hodes 34 variables listed Trace Expression VIOUT VIIN Cancel Help Figure 9 Add Traces window JVdS 2006 9 2 You can also add traces using the Voltage Markers in the schematic From the PSPICE menu select MARKERS VOLTAGE LEVELS Place the makers on the Out and In node When done right click and select End Mode 7 SCHEMATIC PAGE Figure 10 Using Voltage Markers to show the simulation result of V out and V in 3 Go to back to PSpice You will notice that the waveforms will appear 4 You can adda second Y Axis and use this to display e g the current in Resistor R2 as shown below Go to PLOT Add Y Axis Next add the trace for I R2 5 You can also use the cursors on the graphs for Vout and Vin to display the actual values at certain points Go to TRACE CURSORS DISPLAY 6 The cursors will be associated with the fi2. s guide or in the Spice Tutorial http www seas upenn edu jan spice Ri 10k In Out WT D We 20 TO 5m TR 0 1u TF 0 1u Pi 400m PER 500m PER 500m li Om IZ im TR 0 1u C1 uF Figure 14 Circuit with a PULSE voltage and current source 7 After doing the transient simulation results can be displayed as was done before 8 The last example of a transient analysis is with a sinusoidal signal VSIN The circuit is shown below We made the amplitude 10V and frequency 10 Hz JVdS 2006 12 R1 10k Figure 15 Circuit with a sinusoidal input 9 Create a Simulation Profiler for the transient analysis and run PSpice 10 The result of the simulation for Vout and Vin are given in the figure below transsine S CHEMATIC1 TranSine dat active I I 4 245 h 4 r te kA 560m 395 747n 46 813m tL ke Hs ULIH lot UCOUTS Figure 16 Transient simulation with a sinusoidal input 2 4 2 AC Sweep Analysis The AC analysis will apply a sinusoidal voltage whose frequency is swept over a specified range The simulation calculates the corresponding voltage and current amplitude and phases for each frequency When the input amplitude is set to 1V then the output voltage is basically the transfer function In contrast to a sinusoidal transient analysis the AC analysis is not a time domain simulation but rather a simulation of the sinusoidal steady state of the circuit When
3. Inductors e Mutual inductors e Transmission lines e Operational amplifiers e Switches e Diodes e Bipolar transistors e MOS transistors e JFET e MESFET e Digital gates e and other components see users manual JVdS 2006 2 2 PSpice with OrCAD Capture release 9 2 Lite edition Before one can simulate a circuit one needs to specify the circuit configuration This can be done in a variety of ways One way 1s to enter the circuit description as a text file in terms of the elements connections the models of the elements and the type of analysis This file is called the SPICE input file or source file and has been described somewhere else see http www seas upenn edu 7Ejan spice spice overview html An alternative way is to use a schematic entry program such as OrCAD CAPTURE OrCAD Capture is bundled with PSpice Lite AD on the same CD that is supplied with the textbook Capture is a user friendly program that allows you to capture the schematic of the circuits and to specify the type of simulation Capture is non only intended to generate the input for PSpice but also for PCD layout design programs The following figure summarizes the different steps involved in simulating a circuit with Capture and PSpice We ll describe each of these briefly through a couple of examples Step 1 Circuit Creation with Capture Step 2 Specify type of simulation e Create anew Analog mixed AD e Create a simulation profile project e Select
4. Integrated Circuits Emphasis PSpice is a PC version of SPICE which is currently available from OrCAD Corp of Cadence Design Systems Inc A student version with limited capabilities comes with various textbooks The OrCAD student edition is called PSpice AD Lite Information about Pspice AD is available from the OrCAD website http www orcad com pspicead aspx The PSpice Light version has the following limitations circuits have a maximum of 64 nodes 10 transistors and 2 operational amplifiers SPICE can do several types of circuit analyses Here are the most important ones e Non linear DC analysis calculates the DC transfer curve e Non linear transient and Fourier analysis calculates the voltage and current as a function of time when a large signal is applied Fourier analysis gives the frequency spectrum e Linear AC Analysis calculates the output as a function of frequency A bode plot is generated e Noise analysis e Parametric analysis e Monte Carlo Analysis In addition PSpice has analog and digital libraries of standard components such as NAND NOR flip flops MUXes FPGA PLDs and many more digital components This makes it a useful tool for a wide range of analog and digital applications All analyses can be done at different temperatures The default temperature is 300K The circuit can contain the following components e Independent and dependent voltage and current sources e Resistors e Capacitors e
5. NM4007 Scale 290 0 90 0 60 Figure 4 2 4 Part Symbol Window allowing you to edit the part The example shown here is a NMOS symbol without a separate bulk contact In that case the source and bulk are automatically shorted together JVdS 2006 28 d The red line on the Parts symbol correspond to pins These can be added by clicking on the Place Pin icon on the right side menu bar or PLACE PIN menu This will open the Place Pin window shown below e You can edit the pins by first selecting it and then right clicking and selecting Edit Properties The pin name and type are important In general you should not change the pin names since these relate back to the Spice model The pin type is usually Input or Output If you make a pin a Power type it will be invisible in the part symbol For shape you can select Line or Short which corresponds to a short line Check out the other options In case you create a symbol for a subcircuit you can give the pin numbers that correspond to those of the datasheet f When the part symbol is finished save the library You are now ready to use your newly created library and symbols Before doing a simulation you need to add the library to the library path in both the schematic and the simulator setting See section on Adding Vendor Libraries above Place Pin an X p q Line Cancel NM urober Type hil Input E User Properties width Help 0 Scalar C
6. can change the X axis by double clicking on it Figure 3 5 3 gives the Fourier spectrum with the main peak corresponding to the carrier frequency of 5kHz and two side peaks at 4 5 and 5 5 kHz indicating that the modulating frequency is 500Hz You can use the cursors to get accurate readings Any j l l 7 i 3 li i o UCAN Figure 3 5 2 Simulated waveform transient analysis of the circuit above with A 1V f 200 Hz f 5kHz and m 0 5 8S Din BA Be of a Zz o UCAM Frequency Figure 3 5 3 Fourier spectrum of the waveform of Figure 3 5 2 JVdS 2006 23 3 6 Center Tap Transformer There is no direct model in PSpice for a center tap transformer However one can use mutually coupled inductors to simulate a center tap transformer Figure 3 6 1 shows the schematic of the circuit We used one primary inductor L1 and two secondary inductors L1 and L2 put in series In addition we added a K Linear element E K1 K_ near COUPLING 1 R WOFF OV VAMIPL 1 FREQ 60 om Figure 3 6 1 Circuit with Center Tap Transformer with a ratio of 10 1 After placing the element on the schematic give each element its value Use for the input voltage a sinusoid with amplitude of 100 V and frequency 60 Hz Notice that we added a small resistor R1 in series with the voltage source and the inductor This was needed to prevent a short circuit in DC Spice would give en error without this resistor We have kept it smal
7. ee eee i aam aI ammm 87 948m Sea a ee ee ER 69 5170 18 431m 776 627m iOi U OUT uU IH Figure 3 4 2 Simulation results of the rectifier circuit 3 4 2 Parametric Sweep It is interesting to see the effect of the load resistance on the output voltage and its ripple voltage This can be done using the PARAM part PARAMETERS R1 RLvral 500 TR Lval Figure 3 4 3 Circuit used for the parametric sweep of the load resistor a Adding the Parameter Part d JVdS 2006 Double click on the value 500 Ohms of the load resistor R1 to Rval Use curly brackets PSpice interprets the text between curly brackets as an expression that it evaluate to a numerical expression Click OK when done Add the PARAM part to the circuit You ll find this part in the SPECIAL library Double click on the PARAM part This will open a spreadsheet like window showing the PARAM definition You will need to add a new column to this spread sheet Click on NEW COLUMN and enter for Property Name Rlval without the curly brackets You will notice that the new column Rlval has been created Below the Rlval enter the initial value for the resistor lets make it 500 as shown in Figure 3 4 4 below 19 Property Editor a i Parts A Schematic Nets A Pins A Title Blocks E H z Figure 3 4 4 Property Editor window for the PARAM part showing the newly created Rlval column While the cell in which you entered the
8. enter the name of the voltage source to be swept V1 The start and end values and the step need to be specified 0 20 and 0 1V respectively see Fig below Simulation Settings DC Sweep a EJ General Analysis Include Files Libraries Stimulus Options Data Collection Probe windows Analysis type Sweep variable f Yoltage source Name Current source Model tupe Options Global parameter Primary Sweep D aeia Model name C Secondar Sweep _ L Monte Carlo Worst Case Temperature Parameter rama Parametric Sweep L Temperature Sweep Save Bias Point Load Bias Point Sweep type a Start value End value Logarithmic Decade si Increment i Value list Cancel Apply Help Figure 7 Setting for the DC Sweep simulation 3 Run the simulation PSpice will generate an output file that contains the values of all voltages and currents in the circuit JVdS 2006 8 2 3 Step 3 Displaying the simulation Results PSpice has a user friendly interface to show the results of the simulations Once the simulation is finished a Probe window will open File Edit View Simulation Trace Plot Tools Window Help aS iS Sus Gs 2c il SCHEMATICT DC Sweep gt a Qae Mies KKB A MAA Z b EE L b au ami examplerc SCHEMATIC1 DC Sweep dat active Ea examplerc S
9. the circuit contains non linear element such as diodes and transistors the elements will be replaced their small signal models with the parameter values calculated according to the corresponding biasing point In the first example we ll show a simple RC filter corresponding to the circuit of Figure 17 JVdS 2006 13 R1 10k Tac Rz 1 SuF Ode 10k Figure 17 Circuit for the AC sweep simulation Create a new project and build the circuit For the voltage source use VAC from the Sources library Make the amplitude of the input source 1V Create a Simulation Profile In the Simulation Settings window select AC Sweep Noise Enter the start and end frequencies and the number of points per decade For our example we use 0 1Hz 10 kHz and 11 respectively Run the simulation 7 In the Probe window add the traces for the input voltage We added a second window to display the phase in addition to the magnitude of the output voltage The voltage can be displayed in dB by specifying Vdb out in the Add Trace window type Vdb out in the Trace Expression box For the phase type VP out 8 An alternative to show the voltage in dB and phase is to use markers on the schematics PSPICE MARKERS ADV ANCED dB Magnitude or Phase of Voltage or current Place the markers on the node of interest 9 We used the cursors in Figure 18 to find the 3dB point The value is 6 49 Hz corresponding to a time constant of 25 ms RIIIR2 C At 10 Hz the attenu
10. value 500 still selected click the DISPLAY button You can now specify what to display select Name and Value Click OK Click the APPLY button before closing the Property editor Save the design b Create the Simulation Profile for the Parametric Analysis TS JVdS 2006 Select PSPICE NEW_SIMULATION_PROFILE Type in the name of the profile e g Parametric In the Simulation Setting window select Analysis Tab if the window does not open For the Analysis type select Transient or the type of analysis you intend to perform in this example we ll do a transient analysis Under Option slect Parametric sweep as shown in Figure 3 4 5 For the Sweep Variable select Global Parameter and enter the Parameter name Rlval Under sweep type give the start end and increment for the parameter We ll used 250 1kOhm and 250 respectively see Figure 3 4 5 Click OK 20 Simulation Settings Parametric Time Domain Transient hd Hame OG type i General Settings Model name Monte Carlo orst Case Parametric Sweep Temperature Sweep Save Bias Point Load Bias Point Figure 3 4 5 Window for the Simulation Settings of the Parametric Sweep c Run Spice and Display the waveforms a Run PSpice b When the simulation is finished the Probe window will open and display a pop up box with the Available Selection Select ALL and OK c The multiple traces will show as given in Figure 3 4 6 d You can use th
11. Bus e Pin visible Figure 4 2 5 Place Pin window References p lt w a aS a OrCAD website for PSpice http www orcad com pspicead aspx has application notes download examples and interesting links OrCAD website for CAPTURE http www orcad com orcadcapture aspx PSpice User s manual OrCAD Corp Cadence Design Systems Inc PSpice Reference Guide OrCAD Corp Cadence Design Systems Inc PSpice Library Guide OrCAD Capture User s Guide Cadence Design Systems Inc OrCAD Capture User s Guide OrCAD Corp Cadence Design Systems Inc SPICE Tutorial http www seas upenn edu jan spice A Vladimirescu The Spice Book J Wiley amp Sons New York 1994 B Carter Using Texas Instruments Spice Models in PSpice Application Report SLOAO70 Texas Instruments Dallas TX September 2001 JVdS 2006 29 10 A Sedra and K C Smith Microelectronic Circuits Oxford University Press 2004 with accompanying Rom CD containing Spice Circuit Examples Jan Van der Spiegel 2006 jan_at_seas upenn edu Updated March 19 2006 JVdS 2006 30
12. Editor Window in OrCad Capture JVdS 2006 27 he sedra_lib_lib PSpice Model Editor Lite NHOS5PO File Edit View Model Plot Tools Window Help aza L IP at a el el Models List QECL at ward SUBCET DIN4146 Diode OMJE2Z53 EJT MJE Z243 EJT Q2N 3906 EJT EJT MOS MOS SUBCET Zener diode SUBCET PMOSOPS MOS NMOSOPS MOS Level 1 Model for NMOS in model Sum CMOS Technology fereated by Anas Hamoui Olivier Trescases model NMOSSPO NMOS Level 1 VTO 1 GAMM4 1 4 PHI 0 7 LD 0 7E 06 WD 0 Uo 750 LAMBDA 0 01 TOZ 85E 9 PR 0 7 CJ 0 4E 3 CISW 0 8E 9 MJ 0 5 MISW 0 5 CGDO 0 4E 9 JS 1E 6 CGBO 0 2E 9 CGSO0 0 4E 9 rll lal rs Figure 4 2 3 Library sedra_lib lib showing the various devices in the library file The left window pane list all the devices and subcircuits The right pane shows the model of the NWOSSPO highlighted on the left c To edit the symbol of any of the devices double click on it in the Library Editor window Lets select e g the NMOSS5PO device This will open the Part Symbol window as shown in Figure 4 2 4 OrCad Capture is smart enough to know when a model corresponds to a transistor and will create a transistor model as shown in Figure 4 2 4 However for subcircuits is will usually give you a generic box You can than modify this box using the editing tools of Capture E Orcad Capture Lite Edition ESE216LIB Bi Fie Edit wiew Place Options Window Help rey
13. University of Pennsylvania Department of Electrical and Systems Engineering PSPICE A brief primer Contents 1 Introduction 2 Use of PSpice with OrCAD Capture 2 1 Step 1 Creating the circuit in Capture 2 2 Step 2 Specifying the type of analysis and simulation BIAS or DC analysis DC Sweep simulation 2 3 Step 3 Displaying the simulation Results 2 4 Other types of Analysis 2 4 1 Transient Analysis 2 4 2 AC Sweep Analysis 3 Additional Circuit Examples with PSpice 3 1 Transformer circuit 3 2 AC Sweep of Filter with Ideal Op amp Filter circuit 3 3 AC Sweep of Filter with Real Op amp Filter Circuit 3 4 Rectifier Circuit peak detector and the use of a parametric sweep Peak Detector simulation Parametric Sweep 3 5 AM Modulated Signal 3 6 Center Tap Transformer 4 Adding and Creating Libraries Model and Part Symbol files 4 1 Using and Adding Vendor Libraries 4 2 Creating PSpice Symbols from an existing PSpice Model file 4 3 Creating your own PSpice Model file and Symbol Parts References 1 INTRODUCTION SPICE is a powerful general purpose analog and mixed mode circuit simulator that 1s used to verify circuit designs and to predict the circuit behavior This is of particular importance for integrated circuits It was for this reason that SPICE was originally developed at the Electronics Research Laboratory of the University of California Berkeley 1975 as its name implies JVdS 2006 1 Simulation Program for
14. apture the transformer TX is modeled by the part XFRM_LINEAR of the Analog Library ee gt 20 730m 169 878 20 736m 16 983 8 800 152 886 JVdS 2006 15 Figure 3 1 3 Results of the transient simulation of the above circuit 3 2 AC Sweep of Filter with Ideal Op amp Filter circuit The following circuit will be simulated with PSpice ut Figure 3 2 1 Active Filter Circuit with ideal op amp We have used off page connectors OFFPAGELEFT R from the CAPSYM library or by clicking on the off page icon for the input and outputs The name of the connectors can be changed by double clicking on the name of the off page connector By giving the same name to two connectors or nodes the two nodes will be connected no wires are needed For te voltage source we used the VAC from the SOURCE Library We gave it an amplitude of 1V so that the output voltage will correspond to the amplification or transfer function of the filter In the Simulation Analysis select AC Sweep and enter the starting ending frequency and the number of points per decade The result is given in the figure below The magnitude is given on the left Y axis while the phase is given by the right Y axis The cursors have been used to find the 3db points of the bandpass filters corresponding to 0 63 Hz and 32 Hz for the low and high breakpoints respectively These numbers correspond to the values of the time constants given in Fig 3 2 1 The pha
15. ation of Vout is 11 4db or a factor of 3 72 This corresponds to the value of the amplitude of the output voltage obtained during the transient analysis of Figure 16 above ee ea UPCOUT 865 842m 6 4938 em ee A E EUDE OUT Freguenc JVdS 2006 14 3 Additional Circuit Examples with PSpice 3 1 Transformer circuit SPICE has no model for an ideal transformer An ideal transformer is simulated using mutual inductances such that the transformer ratio N1 N2 sqrt L1 L2 The part in PSpice is called TRRM_LINEAR in the Analog Library Make the coupling factor K close to or equal to one ex K 1 and choose L such that wL gt gt the resistance seen be the inductor The secondary circuit needs a DC connection to ground This can be accomplished by adding a large resistor to ground or giving the primary and secondary circuits a common node The following example illustrates how to simulate a transformer ri Figure 3 1 1 Circuit with ideal transformer For the above example lets make wL2 gt gt 500 Ohm or L2 gt 500 60 2p1 lets make L2 at least 10 times larger ex L2 20H L1 can than be found from the turn ratio L1 L2 N1 N2 For a turn ratio of 10 this makes L1 L2x100 2000H The circuit as entered in PSpice Capture is shown in Figure 3 1 2 and the result in Figure 3 1 3 Ri io THT WOFF 0w VAMPL 170 FREQ 60 10OMEG Figure 3 1 2 Circuit with ideal transformer as entered in PSpice C
16. ble see the next section on how to create a Part Symbol In some cases you may want to add model libraries and symbols from vendors that contain the devices you want to use in your design The ORCAD PSpice website list many vender contributed models You can download these files You will need both the model definition file with extension 11ib and the symbol file extension o1b When entering the symbols in the schematic you will need to add the library You need also to tell the simulator that the file exists You do this in the Schematics when defining the Simulation Profile In the Simulation Setting window select the Libraries tab In the Filename box enter the name of the new library the full path name or the library name 1f it is located in the same folder as the standard libraries You can make the library modes global so that it will be available for every schematic or you can keep it local for the current schematic only Figure 4 1 shows who we added the library nat_semi lib as a global library click on the Add as Global JVdS 2006 25 Simulation Settings trang eC x General Analysis Include Files Libraries Stimulus Options Data Collection Probe Window Browse rat_semu lib Add az Global nom lib Add to Design Edit Ehange Filename Library files Pi ae Library Path C Program Files OrcadLite Capture Libra FS pice Browse Cancel Apoly Help F
17. double clicking on the number next to the resistor You can also change the name of the resistor Do the same for the capacitor and voltage and current source If you haven t done so yet you can assign names to nodes e g Out and In nodes Save the project JVdS 2006 6 2 1 4 Netlist The netlist gives the list of all elements using the simple format R name nodel node2 value C_name nodex nodey value etc 1 You can generate the netlist by going to the PSPICE CREATE NETLIST menu 2 Look at the netlist by double clicking on the Output name net file in the Project Manager Window in the left side File window Note on Current Directions in elements The positive current direction in an element such as a resistor is from node 1 to node 2 Node 1 is either the left pin or the top pin for an horizontal or vertical positioned element e g a resistor By rotating the element 180 degrees one can switch the pin numbers To verify the node numbers you can look at the netlist e g R_R2 nodel node2 10k e g R_R2 O OUT 10k Since we are interested in the current direction from the OUT node to the ground we need to rotate the resistor R2 twice so that the node numbers are interchanged R_R2 OUT O 10k 2 2 Step 2 Specifying the type of analysis and simulation As mentioned in the introduction Spice allows you do to a DC bias DC Sweep Transient with Fourier analysis AC analysis Montecarlo worst case sweep Parameter sweep and Tempe
18. e cursors to determined specific valueson the traces you can also adjust the axis by double clicking on the Y and X axes JVdS 2006 21 rechihersweep S CHEMATIC Parametric dat active 7 UCOUT Figure 3 4 6 Results of the parametric sweep of the load resistor varying from 250 to 1000 Ohm in steps of 250 Ohm 3 5 AM Modulated Signal AM Modulation An Amplitude modulated AM signal has the expression Vamlt A Vm cos 2 Zfmt cos 2 afet A 1 m cos 2 afmt cos 2 afet in which a sinusoidal high frequency carrier waveform cos 2 7f t is modulated by a sinusoidal modulating of frequency fm The modulating frequency can be any signal For this example we ll assume it is a sinusoid The modulation index is called m To generate a AM signal in PSpice we can make use of the Multiplication function MULT that can be found in the ABM library Figure 3 51 shows the schematic that generates the AM signal over the resistor R1 AM modulated signal OFF 0w AMPL 1 wear Ne FREQ Sk Hz WORF 1 WAMIPL 0 54 FREQ S00Hz2 Figure 3 5 1 Schematic for the generation of an AM signal JVdS 2006 22 The result of a transient simulation is shown in the figure below One can also look at the Fourier of the simulated output signal In the Probe window click on the FFT icon located on the top toolbar or go to the PSPICE FOURIER menu The Fourier spectrum of the displayed trace will be shown You
19. g on the Add Library button This will bring up the Add Library window Select the desired library For Spice you should select the libraries from the Capture Library PSpice folder Analog contains the passive components R L C mutual inductane transmission line and voltage and current dependent sources voltage dependent voltage source E current dependent current source F voltage dependent current source G and current dependent voltage source H Source give the different type of independent voltage and current sources such as Vdc Idc Vac Iac Vsin Vexp pulse piecewise linear etc Browse the library to see what is available Eval provides diodes D bipolar transistors Q MOS transistors JFETs J real opamp such as the u741 switches SW_tClose SW_tOpen various digital gates and components Abm contains a selection of interesting mathematical operators that can be applied to signals such as multiplication MULT summation SUM Square Root SWRT Laplace LAPLACE arctan ARCTAN and many more Special contains a variety of other components such as PARAM NODESET etc JVdS 2006 5 4 Place the resistors capacitor from the Analog library and the DC voltage and current source You can place the part by the left mouse click You can rotate the components by clicking on the R key To place another instance of the same part click the left mouse button again Hit the ESC key when done with a part
20. icular element You can add initial conditions to the capacitor Double click on the part this will open the Property window that looks like a spreadsheet Under the column labeled IC enter the value of the initial condition e g 2V For our example we assume that IC was OV this is the default value After placing all part you need to place the Ground terminal by clicking on the GND icon on the right side toolbar see Fig 3 When the Place Ground window opens select GND CAPSYM and give it the name 0 i e zero Do not forget to change the name to 0 otherwise PSpice will give an error or Floating Node The reason is that SPICE needs a ground terminal as the reference node that has the node number or name O zero Place Ground E E X k Cancel GHD YLAPS TM GAO Design Cache Add Library GND EARTH CAP SYM GNO_FIELD SIGNAL CA Remove Library SEERA dadai Help Libraries CAPS YM Design Cache Give it the name 0 zero Figure 5 Place the ground terminal box the ground terminal should have the name 0 Now connect the elements using the Place Wire command from the menu PLACE WIRE or by clicking on the Place Wire icon You can assign names to nets or nodes using the Place Net Alias command PLACE NET ALIAS menu We will do this for the output node and input node Name these Out and In as shown in Figure 2 2 1 3 Assign Values and Names to the parts l Change the values of the resistors by
21. igure 4 1 Adding a library 4 2 Creating Symbol Parts file from a Model file In many cases you may have the models of devices available but not the Part Symbol that is used in PSpice Capture In this case you need to create the symbol file olb In many cases you will have a model file that contains models of many devices including subcircuits This section describes how to use the model file to create a Part Symbol for the corresponding devices in the model file 9 The model file is a text file that can be read using a text editor e g Notepad In many cases existing vendor Spice files will have the extension cir or mod We assume that you have such a file available but not the Part Symbol 4 2 1 Open the PSpice Model Editor this program came with the PSpice package a Under the FILE Menu select NEW b Next under the MODEL menu select IMPORT and find the model file for which you need to create the Part Symbol file This will open the model file c Save this file with the extension lib and put it in a directory where you store the library files you can put it in any directory the default libraries are stored in Program Files OrCadLite Capture Library PSpice d The next step is to create the Parts for Capture While the model file lib is still open go to FILE CREATE_CAPTURE_FILE menu A window Create parts for Library will pop us as shown below Click on the top Browse Button and find the location of the model library
22. is stored lib This will automatically fill the Output Part Library entry with the same file name as the model library but with the olb extension JVdS 2006 26 Create Parts for Library Enter Input Model Library OroadLite Capture Library PSpice ESE 21 6LIB LIB Enter Output Part Library Ko rcadLitesCapture Librarp PS pice ESE 21 6LIB olb Browse OK Cancel Help Figure 4 2 1 Create Parts for Library window In this example we created a Model Library called ESE216LIB lib and Parts ESE216LIB olb e Click the OK button A window will open giving the status of the library creation This should give you no errors f Click OK in the Status window The next step is to edit the Part Symbols that you just created 4 4 2 Editing the Part Symbol a Open OrCad Capture b Go to the FILE OPEN LIBRARY menu Browse for the location of the newly created file e g ESE216LIB OLB Click OK This will open the PCB window fpr the library as shown below In our example our library contains two devices NMOS and PMOS devices In practical cases the library can contain many different devices and subcircuits An example is the sedra_lib lib and sedra_lib olb that comes with the textbook 10 shown in Figure 4 2 3 PLE cs Hierarchy Design Resources DF c program Filestorcadlite capture library tf C WM400 P4007 Library Cache 4 Library E Oubpuks C Referenced Projects Figure 4 2 2 Library
23. l equal to 1 Ohm Assume that we want to have a step down transformer with a ratio of 10 1 to each secondary output The ratios of the inductors L2 L1 and L3 L1 must then be equal to 1 10 or sqrt L2 L1 0 1 We made L1 1000 and L2 L3 10H Double click on the K Linear element and type under the column headings for L1 L2 L3 the values LP Ls1 Ls2 When done click the APPLY button and close the properties window Go to PSpice CREATE_NETLIST to generate the netlist To see the list go to the Project Manager and double click on OUTPUTS name net file The netlist looks as follows source CENTERTAPTRANSFOR2 Kn Ki L_Lp L_Lsl L_Ls2 1 L_Lp O NOO241 1000 L Lsl 0 VOL 10 L_Ls2 vo2 0 10 V_V1 NOO203 O SIN OV LOUY 60 0 0 0 R_R1 N00203 N00241 1k R_R2 Or VOL 1k R_R3 VO2 0 1k Create a new Simulation Profile Transient with Time to run 50ms The result is shown in Figure 3 6 2 Notice that the max output is 10V as one would expect from a transformer ratio of 10 1 with an input voltage of 100Vmax The two outputs are 180 degrees out of phase JVdS 2006 24 C centertaptransfor2 SCHEMATIC1 Trans dat acti Jo 1800 7s Figure 3 6 2 Output of the circuit of Fig 3 6 1 4 Adding and Creatine Libraries Model and Parts files 4 1 Using and Adding Vendor Libraries We assume that the model lib as well as the Part Symbols files olb is available from the vendor In case only the model file is availa
24. lect Create Blank Project oe A new page will open in the Project Design Manager as shown below Et Orcad Capture Lite Edition File Edit View Place Macro PSpice Accessories Options Window Help alela a slale eer gt Mee qJ lel gt Sle9 2 8 v Ea pwl iy Tutoriali opi i 7 SCHEMATICI PAGE1 AR Analog or Mined A D a i Hierarchy ean Pas AE Eea Design Resources Add Wires Hi HBA Mutorial den L fg SCHEMATIC Add Node name ED PAGE A t o H E Design Cache Ad junction A C3 Library er GHO C Outputs H PSpice Resources Add Ground m Add Off page connectors N 4 Pre O items selected Scale 100 0 60 Y 2 10 ole JVdS 2006 4 Figure 3 Design manager with schematic window and toolbars OrCAD screen capture 2 1 2 Place the components and connect the parts 1 Click on the Schematic window in Capture 2 To Place a part go to PLACE PART menu or click on the Place Part Icon This will open a dialog box shown below 0 Cancel Add Library Remove Library Part Search Help i Normal torent Parts per Pkg 1 Patt ki Type Homogeneous Figure 4 Place Part window 3 Select the library that contains the required components Type the beginning of the name in the Part box The part list will scroll to the components whose name contains the same letters If the library is not available you need to add the library by clickin
25. rature sweep We will first explain how to do the Bias and DC Sweep on the circuit of Figure 2 2 2 1 BIAS or DC analysis 1 With the schematic open go to the PSPICE menu and choose NEW SIMULATION PROFILE 2 Inthe Name text box type a descriptive name e g Bias From the Inherit From List select none and click Create 4 When the Simulation Setting window opens for the Analyis Type choose Bias Point and click OK 5 Now you are ready to run the simulation PSPICE RUN 6 A window will open letting you know if the simulation was successful If there are errors consult the Simulation Output file 7 To see the result of the DC bias point simulation you can open the Simulation Output file or go back to the schematic and click on the V icon Enable Bias Voltage Display and I icon current display to show the voltage and currents see Figure 6 oS JVdS 2006 7 The check the direction of the current you need to look at the netlist the current is positive flowing from nodel to nodel see note on Current Direction above C1 SuF TOO Ou rl i Figure 6 Results of the Bias simulation displayed on the schematic 2 2 2 DC Sweep simulation We will be using the same circuit but will evaluate the effect of sweeping the voltage source between 0 and 20V We ll keep the current source constant at 1mA p Create a new New Simulation Profile from the PSpice Menu We ll call it DC Sweep 2 For analysis select DC Sweep
26. rst trace as indicated by the small small rectangle around the legend for V out at the bottom of the window Left click on the first trace The value of the x and y axes are displayed in the Probe window When you right click on V out the value of the second cursor will be given together with the difference between the first and second cursor 7 To place the second cursor on the second trace for V in right click the legend for Vdn You ll notice the outline around V in at the bottom of the window When you right click the second trace the cursor will snap to it The values of the first and second cursor will be shown in Probe window You can chance the X and Y axes by double clicking on them 9 When adding traces you can perform mathematical calculations on the traces as indicated in the Add Trace Window to the right of Figure 9 7 JVdS 2006 10 OIUCOUT UCIN Z 7 I R2 U ui Figure 11 Result of the DC sweep showing Vout Vin and the current through resistor R2 Cursors were used for V out and V in 2 4 Other types of Analysis 2 4 1 Transient Analysis We ll be using the same circuit as for the DC sweep except that we ll apply the voltage and current sources by closing a switch as shown in Figure 12 C1 SuF Figure 12 Circuit used for the transient simulation 1 Insert the SW_TCLOSE switch from the EVAL Library as shown above Double click on the switch TCLOSE value and enter the value when the s
27. se at these points is 135 and 224 degrees JVdS 2006 16 630 957m 31 623 f 30 992 Figure 3 2 2 Results of the AC sweep of the Active Filter Circuit of the figure above 3 3 AC Sweep of Filter with Real Op amp Filter circuit The circuit with a real op amp is shown below We selected the U741 op amp to build the filter The simulation results are shown in Figure 3 3 2 As one would expect the differences between the filter with the real and ideal op amps are minimal in this frequency range Dut 2 WAT 15g Figure 3 3 1 Active Filter Circuit with the U741 Op amp JVdS 2006 17 628 876n 32 418 16 9086 31 790 34 602m 18mHz 1 0Hz 186H2 WPCOUT 2 of Udb 0UT UiC2 2 LA Su Figure 3 3 2 Results of the AC sweep of the Active Filter Circuit with real Op amp U741 of the figure above 3 4 Rectifier Circuit peak detector and the use of a parametric sweep 3 4 1 Peak Detector simulation OFF oh AMPL 15 FREQ 60Hz Fiload O00 Figure 3 4 1 Rectifier circuit with the DIN4148 diode and a load resistor of 500 Ohm The results of the simulation are given in Fig 3 4 2 The ripple has a peak to peak value of 777mV as indicated by the cursors The maximum output voltage is 13 997V which is one volt below the input of 15V JVdS 2006 18 2 HU es EJ rectifier SCHEMATIC1 Transient dat active o iol xj Enp a ee ee 4 et en Ce
28. type of analysis e Place circuit parts o Bias DC sweep e Connect the parts Transient AC sweep e Specify values and names e Run PSpice Step 3 View the results e Add traces to the probe window e Use cursors to analyze waveforms e Check the output file if needed e Save or print the results Figure 1 Steps involved in simulating a circuit with PSpice The values of elements can be specified using scaling factors upper or lower case T or Tera 1E12 U or Micro E 6 G or Giga E9 N or Nano E 9 MEG or Mega E6 P or Pico E 12 K or Kilo E3 F of Femto E 15 M or Milli E 3 Both upper and lower case letters are allowed in PSpice and HSpice As an example one can specify a capacitor of 225 picofarad in the following ways Z20E 22590 2ZZ500F 229pFarad 225127 0 225 JVdS 2006 3 Notice that Mega is written as MEG e g a 15 megaOhm resistor can be specified as ISMEG ISMEGohm 15meg or 15E6 Be careful not to use M for Mega When you write 15Mohm or 15M Spice will read this as 15 milliOhm We ll illustrate the different types of simulations for the following circuit C1 SuF Figure 2 Circuit to be simulated screen shot from OrCAD Capture 2 1 Step 1 Creating the circuit in Capture 2 1 1 Create new project Open OrCAD Capture Create a new Project FILE MENU NEW_PROJECT Enter the name of the project Select Analog or Mixed AD When the Create PSpice Project box opens se
29. witch closes Lets make TCLOSE 5 ms 2 Setup the Transient Analysis go to the PSPICE NEW SIMULATION PROFILE 3 Give it a name e g Transient When the Simulation Settings window opens select Time Domain Transient Analysis Enter also the Run Time Lets make it 50 ms For the Max Step size you can leave it blank or enter 10us 4 Run PSpice 5 A Probe window in PSpice will open You can now add the traces to display the results In the figure below we plotted the current through the capacitor in the top window and the voltage over the capacitor on the bottom one We use the cursor to find the time constant of the exponential waveform by finding the 0 632 x V out max 9 48 The JVdS 2006 11 cursor gave a corresponding time of 30ms which gives a time constant of 30 5 25ms 5 ms is subtracted because the switch closed at 5ms 5 6ms UCIN fe UCOUT 768 0m 36 8686n dif 176 660n Figure 13 Results of the transient simulation of Figure 12 44 994 94978 54962 6 Instead of using a switch we can also use a voltage source that changes over time This was done in Figure 14 where we used the VPULSE and IPULSE sources from the SOURCE Library We entered the voltage levels V1 and V2 the delay TD Rise and Fall Times Pulse Width PW and the Period PER The values are indicated in the figure below For details on these parameters click here A description of other Spice elements can be found in the User
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