PSPICE - Review

1. PSPICE - Review Kishore C. Acharya

2. Starting Simulation with PSPICE • Launch PSPICE design Manager • Create a New Work Space or Open an Existing one • Launch Schematics • Build Simulation Diagram by drawing on the schematic Kishore Acharya

3. Some PSPICE Commands • CTRL G – Get Components and place • CTRL W – To connect components • CTRL R – Rotate Components • CTRL F – Flip (Horizontally) Component • CTRL R – Rotate Components • CTRL L – Redraw • Hitting escape exits from command • Hitting space bar invokes last command • Pressing F11 Starts Simulation Kishore Acharya

4. Adding Custom Models • From Analysis Menu select item Library and Include Files • Click on Browse • Navigate and Select appropriate .txt file • Click on Add Include Button • Exit Kishore Acharya

5. Attaching Custom Model to a device • The Schematic must be drawn using components from breakout library e.g. Mbreakp, Mbreakn, Qbreak etc. for PMOS, Nmos, BJT etc. respectively • Save Schematic • High Light the device to be attached with the custom model by clicking on it. • From Edit menu select item Model • From the Dialog Box click on Change Model Reference Button and type the name from the custom model text file e.g. CMOSN, CMOSP for Level 3 Model of T15D Kishore Acharya

6. Verification that Custom Model is attached • High Light the Device in Schematic • From Edit Menu select item Model • From the dialog box click on Edit Instance Model (text) • The appropriate Model will be displayed. • Exit by clicking Cancel Button • Clicking Save creates a local copy of the instance model that can be edited without affecting other circuits Kishore Acharya

7. Setup for Simulation – DC Analysis • From Analysis menu select setup • Check DC Analysis box • Click DC Analysis button • On DC Analysis dialog box • Type Source Name (same as in schematic, e.g. Vds) • Set start, final and end values • Click radio buttons Voltage Source and Linear • Click Nested Sweep Button (for nested sweep) otherwise exit. Kishore Acharya

8. Setup for Simulation – DC Analysis Continued • On Nested Sweep dialog box • Type Second Source Name (same as in schematic, e.g. Vgs) • Set start, final and end values • Click radio buttons Voltage Source and Linear • Check Enable Nested Sweep • Exit Nested Sweep Box • Exit Main Sweep Box Kishore Acharya

9. Setup for Simulation – Transient Analysis • From Analysis menu select setup • Check Transient Analysis box • Click Transient Analysis button • On Transient Analysis dialog box • Set print step to 20ns • Set Final time to the appropriate value( usually 4 to 5 times the period of input pulse) • Exit Dialog Box Kishore Acharya

10. Pulse Specification for Transient V2 V1 td tr PW tf PER Example F = 10 Mhz PER = 1/107 = 100 ns PW = 0.45 PER = 45 ns tr = tf = 0.05 PER = 5 ns Select operating Frequency F hz. PER = 1/F, PW = 0.45 PER, tr=tf = 0.05 PER, td = 0 Kishore Acharya

11. Typical Input output waveform for digital circuits Output Waveform Non Inverted Input Pulse Kishore Acharya

12. Typical Input output waveform for digital circuits at the maximum limit Output Waveform Non Inverted Input Pulse At the maximum operating frequency output pulse is not square any more and it barely touches the input pulse. Kishore Acharya

13. Viewing Waveform • Waveform will be displayed automatically if a Voltage Marker from Marker Menu is placed on the desired output • Otherwise go to menu item Trace and select Add Trace • Add trace dialog box will list all available output • Click on the desired output Kishore Acharya

14. Copying Schematic • To copy schematic into another application • Draw a box around the diagram by dragging the mouse (selected items will turn red) • From Edit Menu Select Copy to Clipboard option Kishore Acharya

15. Copying a Waveform • From Edit Menu use Select all command • From Edit menu use Copy command • Note: Only plot data values are copied not the graph • Paste copied data values it into a Microsoft excel • Draw Scatter graph with the data Kishore Acharya