PSpice A/D User's Guide
Contents
1. PSpice A D simulation output window see Figure 4 vm Simulation Profle SCHEMATIC Biag m MN Simulation running circuit file for profile Bias Reading and checking circuit Circuit read in and checked no errors Calculating bias point Bias point calculated Simulation complete Figure 4 PSpice A D simulation output window Performing a bias point analysis To set up a bias point analysis in Capture 1 In Capture switch to CLIPPER OP in the schematic page editor 2 From the PSpice menu choose New Simulation Profile to display the New Simulation dialog box 3 Inthe Name text box type Bias 4 From the Inherit From list select None then click Create The Simulation Settings dialog box appears 5 From the Analysis type list select Bias Point 6 Click OK to close the Simulation Settings dialog box Running PSpice A D To simulate the circuit from within Capture 1 From the PSpice menu choose Run gt PSpice A D simulates the circuit and calculates the bias point information Note Because waveform data is not calculated during a bias point analysis you will not see any plots displayed in the Probe window for this simulation To find out how to view the results of this simulation see Using the simulation output file below 63 Chapter 2 Simulation examples 64 Using the simulation output file The simulation output file acts as an audit trail of the simulation This file optionally2. Y values for the second cursor appear in the cursor window along with the difference dif between the two cursors X and Y values DC sweep analysis C To fine tune the location of the second cursor to 4 volts on the x axis drag the crosshairs until the x axis value of the A2 cursor in the cursor window is approximately 4 0 You can also press shif gt and Shift for tighter control Figure 13 shows the Probe window with both cursors There are also ways to display the placed difference between two voltages as a trace TS cee e In PSpice add the trace expression a gt S mS e mmm V In V Mid 88a 9 M e E A met Pees 2 e In Capture from the PSpice menu point to Markers and choose Voltage Differential Place the two markers on different pins or wires For Help press FT a V in 15 100 SRR ZIS Figure 13 Voltage difference at V In 4 volts To delete all of the traces You can also delete an individual trace by selecting its name in the trace legend and h Delete All T i 1 From the Trace menu choose Delete races then pressing Delt At this point the design has been saved Ifneeded E ample To delete the V In trac dick the OAE i PSN we ae eae as lt text V In located under the plot s eee ana YSIS exercises later using e Save x axis and then press Delete Finding out more about DC sweep analysis T
3. echoes the contents of the circuit file as well as the results of the bias point calculation If there are any syntax errors in the netlist declarations or simulation commands or anomalies while performing the calculation PSpice A D writes error or warning messages to the output file To view the simulation output file 1 From PSpice s View menu choose Output File Figure 5 shows the results of the bias point calculation as written in the simulation output file tant 10 05 98 12 06 18 t PSpice 9 0 Aug 1998 traretet Dg 3 tererter a circuit file for profile Bias iid SMALL SIGNAL BIAS SOLUTION TEMPERATURE 27 000 DEG C TELELELLLLLLLLLLLLLLLLLLEELLLLLE LLL ELLE EEL NODE VOLTAGE NODE VOLTAGE NODE VOLTAGE NODE VOLTAGE IN 0 0000 OUT 0 0000 YCC 5 0000 NW00744 9434 VOLTAGE SOURCE CURRENTS NAE CURRENT vyl 1 229E 03 Vin 9 434 04 TOTAL POWER DISSIPATION 6 15E 03 WATTS v al E clpper SCH Figure Simulation output file 2 When finished close the window Running PSpice A D PSpice A D measures the current through a two terminal device into the first terminal and out of the second terminal For voltage sources current is measured from the positive terminal to the negative terminal this is opposite to the positive current flow convention and results in a negative value in the output file Finding out more about bias point calculations Table 2 1 To find out more about this See this
4. input resistance on the bandwidth and gain of the clipper circuit by e Changing the value of R1 to the expression Rval e Placing a PARAM part to declare the parameter Rval e Setting up and running a parametric analysis to step the value of R1 using Rval R1 lt WAY oO D1N3940 c1 Rval 3 Vin 1 Qs ite ae Iili m V3 SINE I 60 m 0 47u D2 D1 N3940 PARAMETERS Rval 1k l Figure 22 Clipper circuit with global parameter Rval This example produces multiple analysis runs each with a different value of R1 After the analysis is complete you can analyze curve families for the analysis runs using PSpice A D Setting up and running the parametric analysis To change the value of R1 to the expression Rval 1 2 3 4 In Capture open CLIPPER OPJ Double click the value 1k of part R1 to display the Display Properties dialog box In the Value text box replace 1k with Rva1 Click OK To add a PARAM part to declare the parameter Rval 1 2 10 11 12 From Capture s Place menu choose Part In the Part text box type PARAM from the PSpice library SPECIAL OLB then click OK Place one PARAM part in any open area on the schematic page Double click the PARAM part to display the Parts spreadsheet then click New In the Property Name text box enter Rval no curly braces then click OK This creates a new property for the PARAM
5. may be different such as VP Cout 2 VP R4 1 or gt VP R4 2 For more information on Probe windows and trace expressions see Chapter 17 Analyzing waveforms 5 press Ctrl X ra 6 7 8 press Ctrl V 80 From Capture s PSpice menu point to Markers point to Advanced and choose Phase of Voltage Place a Vphase marker on the output next to the Vdb marker Delete the Vdb marker on Mid Switch to PSpice In the Probe window the gain and phase plots both appear on the same graph with the same scale Click the trace name VP Out to select the trace From the Edit menu choose Cut From the Plot menu choose Add Y Axis From the Edit menu choose Paste The Bode plot appears as shown in Figure 21 154 GHz 166Hz 41 OKHZ 16KHZ 1 o VDB OUT 2 a UP OUT E ciooer SCHE 1G6KHZ 1 6NHZ 10HHz 100HHz Frequency Figure 21 Bode plot of clipper s frequency response Finding out more about AC sweep and noise analysis Table 2 2 To find out more about this AC sweep analysis noise analysis based on an AC sweep analysis See this AC sweep analysis on page 10 324 Noise analysis on_ page 10 333 AC sweep analysis 81 Chapter 2 Simulation examples i 82 Note Parametric Analysis is not supported in PSpice A D Basics Parametric analysis This example shows the effect of varying
6. part as shown by the new column labeled Rval in the spreadsheet Click in the cell below the Rval column and enter 1k as the initial value of the parametric sweep While this cell is still selected click Display In the Display Format frame select Name and Value then click OK Click Apply to update all the changes to the PARAM part Close the Parts spreadsheet Select the VP marker and press to remove the marker from the schematic page From the File menu choose Save to save the design Parametric analysis PSpice A D interprets text in curly braces as an expression that evaluates to a numerical value This example uses the simplest form of an expression a constant The value of R1 will take on the value of the Rval parameter whatever it may be Note For more information about using the Parts spreadsheet see the OrCAD Capture User s Guide This example is only interested in the magnitude of the response 83 Chapter 2 Simulation examples To set up and run a parametric analysis to step the value of R1 using Rval 1 From Capture s PSpice menu choose New Simulation Profile The New Simulation dialog box appears 2 Inthe Name text box type Parametric The root schematic listed is the schematic 3 From the Inherit From list select AC Sweep then click page associated with the simulation profile Create JO areen The Simulation Settings dialog box appears 4 Click the Analysis tab 5 Under Opti
7. symbol outlined 70 1 To place cursors on V In and V Mid From PSpice s Trace menu point to Cursor and choose Display Two cursors appear for the first trace defined in the legend below the x axis V In in this example The Probe Cursor window also appears To display the cursor crosshairs a Position the mouse anywhere inside the Probe window b Click to display the crosshairs for the first cursor C Right click to display the crosshairs for the second cursor In the trace legend the part for V In is outlined in the crosshair pattern for each cursor resulting in a dashed line as shown in Figure 11 Place the first cursor on the V In waveform a Click the portion of the V In trace in the proximity of 4 volts on the x axis The cursor crosshair appears and the current X and Y values for the first cursor appear in the cursor window b To fine tune the cursor location to 4 volts on the x axis drag the crosshairs until the x axis value of the Al cursor in the cursor window is approximately 4 0 You can also press 3 and for tighter control Place the second cursor on the V Mid waveform a Right click the trace legend part diamond for V Mid to associate the second cursor with the Mid waveform The crosshair pattern for the second cursor outlines the V Mid trace part as shown in Figure 12 0 Right click the portion on the V Mid trace that is in the proximity of 4 volts on the x axis The X and
8. Q input resistance Note that the Y value for cursor 2 in the cursor box is about 17 87 This indicates that when R1 is set to 10 kQ the small signal attenuation of the circuit at 100Hz is 17 87dB greater than when R1 is 100 From the Trace menu point to Cursor and choose Display to turn off the display of the cursors Delete the trace 87 Chapter 2 Simulation examples Finding out more about parametric analysis Table 2 3 To find out more about this See this parametric analysis Parametric analysis on page 12 364 using global parameters Using global parameters and expressions for values on page 3 107 Performance analysis Performance analysis Note Perfomance Analys ww is not supported in PSpice Performance analysis is an advanced feature in VE A D Basics PSpice A D that you can use to compare the characteristics of a family of waveforms Performance analysis uses the principle of search commands introduced earlier in this chapter to define functions that detect points on each curve in the family After you define these functions you can apply them to a family of waveforms and produce traces that are a function of the variable that changed within the family This example shows how to use performance analysis to view the dependence of circuit characteristics on a swept parameter In this case the small signal bandwidth and gain of the clipper circuit are plotted against the swept input res
9. Run to run the analysis 67 Chapter 2 Simulation examples 68 press Insert press Ctri M Displaying DC analysis results Probe windows can appear during or after the simulation is finished Z SCHEMATIC1 DC Sweep OrCAD PSpice A D clipper SCHEMATIC1 DC Sweep dat Bi Fie Edt View Simulation Trace Plot Tools Window Help 18 x a gt S ren Eea 4 fsouwancrocsnees y u 8 3 amp h OM Fer 96 FS KEE ot Sh a E 2 100 5u ou SU 10u 15u UU E clipper sth I Smmuaton Profle SEMATI DC Sweep x F oi C Sweep E ae TE i Stat 10 VVin 15 End 15 oc hed Simulation complete 4 Analysis Wach A Devices For Help press Fi VVin 15 100 ee Figure 7 Probe window To plot voltages at nets In and Mid 1 From PSpice s Trace menu choose Add Trace 2 Inthe Add Traces dialog box select V In and V Mid 3 Click OK To display a trace using a marker 1 From Capture s PSpice menu point to Markers and choose Voltage Level 2 Click to place a marker on net Out as shown in Figure 8 Veco A R2 ZA Di 3 3k D1N3940 R1 c1 Ne AAA 4 Mid 4 4H out 1k 0 47u v R3 ZS D R4 3 3k D1N3940 5 6k 4 o Veco A N fi y7 ka Vin ov 2a 1 1 o o Figure 8 Clipper circuit with voltage marker on net Out 3 Right click and choose End Mode to stop pl
10. Simulation examples Chapter overview The examples in this chapter provide an introduction to the methods and tools for creating circuit designs running simulations and analyzing simulation results All analyses are performed on the same example circuit to clearly illustrate analysis setup simulation and result analysis procedures for each analysis type This chapter includes the following sections e Example circuit creation on page 2 56 e Performing a bias point analysis on page 2 62 e DC sweep analysis on page 2 66 e Transient analysis on page 2 72 e AC sweep analysis on page 2 77 e Parametric analysis on page 2 82 e Performance analysis on page 2 89 Chapter 2 Simulation examples Example circuit creation This section describes how to use OrCAD Capture to create the simple diode clipper circuit shown in Figure 2 Vcc R2 ZA D 3 3k D1N3940 R1 c1 A n AAA Mid 4 JH sout 1k 0 47u R3 Z D2 R4 3 3k D1N3940 5 6k a lt salt HR Figure 2 Diode clipper circuit To create a new PSpice project 1 From the Windows Start menu choose the OrCAD Release 9 program folder and then the Capture shortcut to start Capture 2 Inthe Project Manager from the File menu point to New and choose Project 3 Select Analog or Mixed Signal Circuit Wizard 4 Inthe Name text box enter the name of the project CLIPPER 5 Click OK then click Finish No special libraries need to
11. able 2 1 To find out more about this See this DC sweep analysis DC Sweep on page 9 306 71 72 Chapter 2 Simulation examples Transient analysis This example shows how to run a transient analysis on the clipper circuit This requires adding a time domain voltage stimulus as shown in Figure 14 Di D1N3940 RI ci Ing syOut lt AAN H gt 1k 0 47u D2 Re D1N3940 5 5k lt S o EJ Jml l s 3 as Ol 2 SINE dl Figure 14 Diode clipper circuit with a voltage stimulus Transient analysis To add a time domain voltage stimulus 1 8 9 From Capture s PSpice menu point to Markers and choose Delete All Select the ground part beneath the VIN source From the Edit menu choose Cut Scroll down or from the View menu point to Zoom then choose Out Place a VSTIM part from the PSpice library SOURCESTM OLB as shown in Figure 14 From the Edit menu choose Paste Place the ground part under the VSTIM part as shown in Figure 14 From the View menu point to Zoom then choose All From the File menu choose Save to save the design To set up the stimulus 1 2 Select the VSTIM part V3 From the Edit menu choose PSpice Stimulus The New Stimulus dialog box appears In the New Stimulus dialog box type SINI Click SIN sinusoidal then click OK In the SIN Attributes dialog box set the first three properties as follows Offset Vo
12. acing markers 4 From the File menu choose Save 5 Switch to PSpice The V Out waveform trace appears as shown in Figure 9 IE SCHEMATIC1 DC Sweep OrCAD PSpice A D clipper SCHEMATIC1 DC Sweep dat Fle Edt View Simulation Trace Plot Took Window Help alaj a o ge seml gt 4 Me ScHEVATIC OC vee gt at hega OieS SAP id KV FMA Bae 160 100 5u w 5U 10 45u U IN Y U MID U OUT u_Vin BB clipper SCH 4 Simulation Profile SCHEMATICT DC Sweep p Simulation n running circuit fle for profle DC Sweep Reading and checking circuit Circuit read in and checked no eors Stat 10 Vyn 15 manie DC Analysis DC Analysis finished Sradsion corgets ETE Anasi A Watch Devices 7 For Help press F1 VVin 15 100 ERNE Oe Figure9 Voltage at In Mid and Out DC sweep analysis 69 Chapter 2 Simulation examples This example uses the cursors feature to view the numeric values for two traces and the difference between them by placing a cursor on each trace Table 10 Association of cursors with mouse buttons cursor 1 left mouse button cursor 2 right mouse button ioiU In U Mid v U Out Figure 11 Trace legend with cursors activated Your ability to get as close to 4 0 as possible depends on screen resolution and window size Figure 12 Trace legend with V Mid
13. adsheet Continue naming the remaining parts until your schematic looks like Figure 2 on page 2 56 To change the values of the parts 1 Double click the voltage label 0V on V1 to display the Display Properties dialog box In the Value text box type 5v Click OK Continue changing the Part Value properties of the parts until all the parts are defined as in Figure 2 on page 2 56 Your schematic page should now have the same parts wiring labels and properties as Figure 2 on page 2 56 To save your design 1 From the File menu choose Save Finding out more about setting up your design About setting up a design for simulation For a checklist of all of the things you need to do to set up your design for simulation and how to avoid common problems see Chapter 3 Preparing a design for simulation Example circuit creation 61 Chapter 2 Simulation examples You can set up a simulation profile to run one analysis at a time To run multiple analyses for example both DC sweep and transient analyses set up a batch simulation For more information see Chapter 8 Setting up analyses and starting simulation The root schematic listed is the schematic page associated with the simulation profile you are creating 62 Running PSpice A D When you perform a simulation PSpice A D generates an output file OUT While PSpice A D is running the progress of the simulation appears and is updated in the
14. and 1 then use the search commands to find certain characteristics of the difference 4 Plot the new trace by specifying a waveform expression press Insert 5 b C From the Trace menu choose Add Trace In the Trace Expression text box type the following waveform expression Vdb Out 1 Vdb OUT 21 Click OK 5 Use the search commands to find the value of the difference trace at its maximum and at a specific frequency a C d The search command tells PSpice to search for the point on the trace where the x axis value is 100 86 From the Tools menu point to Cursor and choose Display Right click then left click the trace part triangle for Vdb Out 1 Vdb Out 21 Make sure that you left click last to make cursor 1 the active cursor From the Trace menu point to Cursor and choose Max From the Trace menu point to Cursor and choose Search Commands In the Search Command text box type the following search forward x value 100 Select 2 as the Cursor to Move option Parametric analysis g Click OK Figure 25 shows the Probe window with cursors aa aaa aaa ea fen J da A F A Probe Curse i A1 100 000 35 776 i A2 100 0909 17 874 N i dif 180 090H 17 902 EE EE EEEE a 18Hz 168KHZ 1 OMHZ 1OMHZ 168MHZ 100Hz 1 OKHZ 1OKHZ a udb out 1 vdb out 21 vjudb out 1 vdb out 21 Frequency Figure 25 Small signal frequency response at 100 and 10 k
15. be configured at this time A new page will be displayed in Capture and the new project will be configured in the Project Manager To place the voltage sources 1 In Capture switch to the schematic page editor 56 From the Place menu choose Part to display the Place Part dialog box Add the library for the parts you need to place a Click the Add Library button b Select SOURCE OLB from the PSpice library and click Open In the Part text box type VDC Click OK Move the pointer to the correct position on the schematic page see Figure 2 and click to place the first part Move the cursor and click again to place the second part Right click and choose End Mode to stop placing parts To place the diodes 1 From the Place menu choose Part to display the Place Part dialog box Add the library for the parts you need to place a Click the Add Library button 0 Select DIODE OLB from the PSpice library and click Open In the Part text box type D1N39 to display a list of diodes Select DIN3940 and click OK Press R to rotate the diode to the correct orientation Click to place the first diode D1 then click to place the second diode D2 Right click and choose End Mode to stop placing parts Example circuit creation ES eS Note There are two sets of library files supplied with Capture and PSpice A D The standard schematic part libraries are found in the directory Capture Library The part li
16. bias point calculations Bias point on page 9 315 65 Chapter 2 Simulation examples Note The default settings for DC Sweep simulation are Voltage Source as the swept variable type and Linear as the sweep type To use a different swept variable type or sweep type choose different options under Sweep variable and Sweep type 66 DC sweep analysis You can visually verify the DC response of the clipper by performing a DC sweep of the input voltage source and displaying the waveform results in the Probe window in PSpice This example sets up DC sweep analysis parameters to sweep Vin from 10 to 15 volts in 1 volt increments Setting up and running a DC sweep analysis To set up and run a DC sweep analysis 1 In Capture from the PSpice menu choose New Simulation Profile The New Simulation dialog box appears In the Name text box type DC Sweep From the Inherit From list select Schematic1 Bias then click Create The Simulation Settings dialog box appears Click the Analysis tab From the Analysis type list select DC Sweep and enter the values shown in Figure 6 DC sweep analysis Simulation Settings Example Primary Sweep _ Secondary Sweep Monte CarloAworst Case Parametric Sweep Temperature Sweep Save Bias Point Load Bias Point Figure6 DC sweep analysis settings 6 Click OK to close the Simulation Settings dialog box 7 From the File menu choose Save 8 From the PSpice menu choose
17. braries that are designed for simulation with PSpice A D are found in the sub directory Capture Library PSpice In order to have access to specific parts you must first configure the library in Capture using the Add Library function pE o When placing parts e Leave space to connect the parts with wires e You will change part names and values that do not match those shown in Figure 2 later in this section 57 Chapter 2 Simulation examples 58 KC To move the text associated w ith the diodes or any other object 1 Click the text to select it then drag the text to a new location To place the other parts 1 From the Place menu choose Part to display the Place Part dialog box 2 Add the library for the parts you need to place a Click the Add Library button 0 Select ANALOG OLB from the PSpice library and click Open 3 Follow similar steps as described for the diodes to place the parts listed below according to Figure 2 The part names you need to type in the Part name text box of the Place Part dialog box are shown in parentheses e resistors R e capacitor C To place the off page connector parts OFFPAGELEFT R click the Place Off Page Connector button on the tool palette Add the library for the parts you need to place a Click the Add Library button b Select CAPSYM OLB from the Capture library and click Open Place the off page connector parts according to Figure 2 To place the grou
18. e used as milli and MEG Meg and meg can all be used for mega However waveform analysis treats M and m as mega and milli respectively 78 From the Place menu choose Part In the Part text box type vac from the PSpice library SOURCE OLB and click OK Place the AC voltage source on the schematic page as shown in Figure 17 Double click the VAC part OV to display the Parts spreadsheet Change the Reference cell to Vin and change the ACMAG cell to 1V Click Apply to update the changes and then close the spreadsheet To set up and run the AC sweep simulation 1 From Capture s PSpice menu choose New Simulation Profile In the Name text box enter AC Sweep then click create The Simulation Settings dialog box appears Click the Analysis tab From the Analysis type list select AC Sweep Noise and enter the settings shown in Figure 19 Simulation Settings Example x General Analysis Include Files Libraries Stimulus Options Data Collection Probe Windows Analysis type AC Sweep Type AC Sweep Noise i C Linear Start Frequency fo Options Logarithmic End Frequency ficoMes General Settings E Mania Carnot Css Decade Point Decade T Parametric Sweep Temperature Sweep m Noise Analysis I Enabled Gutsut yolteoe lV Source a Interval al Cancel Apply Help Figure 19 AC sweep and noise analysis simulation settings AC sweep analys
19. g box click OK To select individual runs click each one separately All 21 traces the entire family of curves for VDB Out appear in the Probe window as shown in Figure 24 To see more information about the section that produced a specific trace double click the corresponding symbol in the legend below the x axis PBB 4 522 sos e ta sae poe cate c scat age tee e ee Ses esdape sen ces S acc ce pe cceescs asset gene sss eS ceet glee sec eset ees specs ecesssesse i 10Hz 109Hz 1 0KHZ 1OKHZ 180KHZ 1 0MHz 10MHz 100MHz 1 0GHz novAo xAY REDO vVAOHXAY 8 UDB Out Fi Figure 24 Small signal response as R1 is varied from 100Q to 10 kQ 2 Click the trace name to select it then press to You can also remove the traces by remove the traces shown removing the VDB marker from your schematic page in Capture 85 Chapter 2 Simulation examples To compare the last run to the first run press 1 From the Trace menu choose Add Trace to display the Add Traces dialog box 2 Inthe Trace Expression text box type the following You can avoid some of the typing for the Vdb Out 1 Vdb Out 21 Trace Expression text box by selecting lick OK V OUT twice in the trace list and inserting CCK OK B text where appropriate in the resulting Note The difference in gain is apparent You can also plot the difference Trace Expression of the waveforms for runs 21
20. is 5 Click OK to close the Simulation Settings dialog box 6 From the PSpice menu choose Run to start the gt simulation PSpice A D performs the AC analysis To add markers for waveform analysis 1 From Capture s PSpice menu point to Markers point Note You must tirst detine a simulation to Advanced then choose db Magnitude of Voltage profile for the AC Sweep Noise analysis 2 Place one Vdb marker on the Out net then place in order to use advanced markers another on the Mid net 3 From the File menu choose Save to save the design AC sweep analysis results PSpice displays the dB magnitude 20log10 of the voltage at the marked nets Out and Mid in a Probe window as shown in Figure 20 below VDB Mid has a lowpass response due to the diode capacitances to ground The output capacitance and load resistor act as a highpass filter so the overall response illustrated by VDB out is a bandpass response Because AC is a linear analysis and the input voltage was set to 1V the output voltage is the same as the gain or attenuation of the circuit 79 Chapter 2 Simulation examples 1 OKHZ 16KHZ 100KHZ 1 6MHZ 10MHz 100HHz Frequency fi Bisioper SCHE gure 20 dB magnitude curves for gain at Mid and Out To display a Bode plot of the output voltage including phase Note Depending upon where the Vphase 1l marker was placed the trace name
21. istance value To plot bandwidth vs Rval using the performance analysis wizard 1 In Capture open CLIPPER OPJ 2 From PSpice s Trace menu choose Performance Analysis The Performance Analysis dialog box appears with information about the currently loaded data and performance analysis in general 3 Click the Wizard button At each step the wizard provides i Cliches button information and guidelines 5 In the Choose a Goal Function list click Bandwidth then click the Next gt button 6 Click in the Name of Trace to search text box and type Click El then double click V Out V Out 7 Click in the db level down for bandwidth calc text box and type 3 8 Click the Next gt button The wizard displays the gain trace for the first run R 100 and shows how the bandwidth is measured This is done to test the goal function Chapter 2 Simulation examples Double click the x axis or press The Trace list includes goal functions only in performance analysis mode when the x axis variable is the swept parameter 90 10 Click the Next gt button or the Finish button A plot of the 3dB bandwidth vs Rval appears Change the x axis to log scale a From the Plot menu choose Axis Settings b Click the X Axis tab Under Scale choose Log d Click OK To plot gain vs Rval manually 1 2 From the Plot menu choose Add Y Axis From the Trace menu choose Add to display the Add Traces dialog box In the F
22. ltage 0 Amplitude 10 Frequency 1kHz BI Click Apply to view the waveform The Stimulus Editor window should look like Figure 15 or press Ctri V Note The Stimulus Editor is not included in PSpice A D vy Basics If you do not have the Stimulus Editor 1 Place a VSIN partinstead of VSTIM and double click it 2 In the Edit Part dialog box click User Properties 3 Set values for the VOFF VAMPL and FREQ properties as defined in step 5 When finished click OK 73 Chapter 2 Simulation examples press nif F12 Transient optione Buntotime ams seconds TSTOP Pint values in the output fle every 20ns seconds Maximum step size seconds T Skip the initial transient bias point calculation SKIPBP Cees e e Output File Options Figure 16 Transient analysis simulation settings 74 Stimulus Editor chppert stl l lojx 2 Ele Edit Stimulus Plot View Tools Window Help lajxi 1 Bg Stimulus Attributes ES Name SINE Type SIN Otfsetvaue 0 i Amplitude 10 Frequency fm Time Delay pooo Damping Factor pooo Phase Angle ct Cancel Figure 15 Stimulus Editor window 7 Click OK 8 From the File menu choose Save to save the stimulus information Click Yes to update the schematic 9 From the File menu choose Exit to exit the Stimulus Editor To set up and run the transient analysis 1 From Ca
23. nction Example circuit creation lt To stop wiring right dick and choose End Wire The pointer changes to the default arrow Clicking on any valid connection point ends a wire A valid connection point is shown as a box see Figure 3 R1 BVA 1k Figure 3 Connection points If you make a mistake when placing or connecting components 1 From the Edit menu choose Undo or dick o 59 Chapter 2 Simulation examples A more efficient way to change the names values and other properties of several parts in your design is to use the Property Editor as follows 1 Select all of the parts to be modified by pressing and clicking each part 2 From the Edit menu choose Properties The Parts Spreadsheet appears Change the entries in as many of the cells as needed and then click Apply to update all of the changes at once 60 To assign names labels to the off page connectors Label the off page connectors as shown in Figure 2 on page 2 56 1 Double click the name of an off page connector to display the Display Properties dialog box In the Name text box type the new name Click OK Select and relocate the new name as desired To assign names to the parts 1 Double click the second VDC part to display the Parts spreadsheet Click in the first cell under the Reference column Type in the new name Vin Click Apply to update the changes to the part then close the spre
24. nd parts 0 click the GND button on the tool palette Add the library for the parts you need to place a Click the Add Library button b Select SOURCE OLB from the PSpice library and click Open Place the ground parts according to Figure 2 To connect the parts 1 From the Place menu choose Wire to begin wiring parts The pointer changes to a crosshair Click the connection point the very end of the pin on the off page connector at the input of the circuit Click the nearest connection point of the input resistor R1 Connect the other end of R1 to the output capacitor Connect the diodes to each other and to the wire between them a Click the connection point of the cathode for the lower diode Move the cursor straight up and click the wire between the diodes The wire ends and the junction of the wire segments becomes visible Click again on the junction to continue wiring d Click the end of the upper diode s anode pin Continue connecting parts until the circuit is wired as shown in Figure 2 on page 2 56 To assign names labels to the nets 1 From the Place menu choose Net Alias to display the Place Net Alias dialog box In the Name text box type Mid Click OK Place the net alias on any segment of the wire that connects R1 R2 R3 the diodes and the capacitor The lower left corner of the net alias must touch the wire Right click and choose End Mode to quit the Net Alias fu
25. ons select Parametric Sweep and enter the settings as shown below This profile specifies that the parameter Rval is to be stepped from 100 to 10k logarithmically with a resolution of 10 General Analysis Include Files Libraries Stimulus Options Data Collection Probe Window Analysis type r Sweep variable 7 points per decade Time Domain Transient C Voltage source Hame or Current source a ree The analysis is run for each value of Rval 2 a ommpop Coe I z General Settings Modelnam Because the value of R1 is defined as went Carowost caso MA Rval the analysis is run for each value of EETA ne E i R1 as it logarithmically increases from Save Bias Point Sweep ype OLoad Bias Poin h tart 1002 to 10 ka in 20 steps resulting in a R Linear B total of 21 runs C Logarithmic Decade SEA Increment fi 0 C Value list Cancel Apply Help Figure 23 Parametric simulation settings 6 Click OK gt 7 From the PSpice menu choose Run to start the analysis 84 Parametric analysis Analyzing waveform families Continuing from the example above there are 21 analysis runs each with a different value of R1 After PSpice A D completes the simulation the Available Sections dialog box appears listing all 21 runs and the Rval parameter value for each You can select one or more runs to display To display all 21 traces 1 Inthe Available Sections dialo
26. pture s PSpice menu choose New Simulation Profile The New Simulation dialog box appears 2 Inthe Name text box type Transient 3 From the Inherit From list select Schematicl DC Sweep then click Create The Simulation Settings dialog box appears 4 Click the Analysis tab 5 From the Analysis list select Time Domain Transient and enter the settings shown in Figure 16 TSTOP 2ms Start saving data after 20ns Transient analysis 6 Click OK to close the Simulation Settings dialog box 7 From the PSpice menu choose Run to perform the analysis PSpice A D uses its own internal time steps for computation The internal time step is adjusted according to the requirements of the transient analysis as it proceeds PSpice A D saves data to the waveform data file for each internal time step To display the input sine wave and clipped wave at V Out 1 From PSpice s Trace menu choose Add Trace 2 In the trace list select V In and V Out by clicking them 3 Click OK to display the traces 4 From the Tools menu choose Options to display the Probe Options dialog box 5 Inthe Use Symbols frame click Always if it is not already enabled 6 Click OK 6 5ms 1 6ns 1 5ms 2 8ns Os o UCIN UCOUT B lt lt Figure 17 Sinusoidal input and clipped output waveforms gt Note The internal time step is different from the Print Step value Print Step controls ho
27. unctions or Macros frame select the Goal Functions list and then click the Max 1 goal function In the Simulation Output Variables list click V out In the Trace Expression text box edit the text to be Max Vdb out then click OK PSpice displays gain on the second y axis vs Rval Figure 26 shows the final performance analysis plot of 3dB bandwidth and gain in dB vs the swept input resistance s 368 1 6K 41 o Bandwidth u Out 3 Z m Max Udb Out Ruval Figure 26 Performance analysis plots of bandwidth and gain vs Reval Performance analysis Finding out more about performance analysis Table 2 4 To find out more about this See this how to use performance RLC filter example on analysis page 12 366 Example Monte Carlo analysis of a pressure sensor on page 13 385 how to use search PSpice A D online Help commands and create goal functions 91
28. w often optional text format data is written to the simulation output file 0UT or press Insert These waveforms illustrate the clipping of the input signal 75 Chapter 2 Simulation examples Finding out more about transient analysis Table 2 1 To find out more about this See this transient analysis for analog Chapter 11 Transient and mixed signal designs analysis transient analysis for digital Chapter 14 Digital designs simulation Includes how to set up time based stimuli using the Stimulus Editor 76 AC sweep analysis AC sweep analysis The AC sweep analysis in PSpice A D is a linear or small signal frequency domain analysis that can be used to observe the frequency response of any circuit at its bias point Setting up and running an AC sweep analysis In this example you will set up the clipper circuit for AC analysis by adding an AC voltage source for a stimulus signal see Figure 18 and by setting up AC sweep parameters om D1N3940 c1 O47u D2 R4 D1N3940 5 6k lt o F vin 2s lt H u Z m KOO Figure 18 Clipper circuit with AC stimulus To change Vin to include the AC stimulus signal 1 In Capture open CLIPPER OPJ 2 Select the DC voltage source Vin and press to remove the part from the schematic page 77 Chapter 2 Simulation examples Note PSpice simulation is not case sensitive so both M and m can b
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