PSPICE - Review Kishore C. Acharya

Kishore Acharya2 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 Acharya3 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 Acharya4 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 Acharya5 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 Acharya6 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 Acharya7 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 Acharya8 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 Acharya9 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 Acharya10 Pulse Specification for Transient tdtd trtr PWtftf PER V1V1 V2V2 Select operating Frequency F hz. PER = 1/F, PW = 0.45 PER, t r =t f = 0.05 PER, td = 0 Example F = 10 Mhz PER = 1/10 7 = 100 ns PW = 0.45 PER = 45 ns t r = t f = 0.05 PER = 5 ns

Kishore Acharya11 Typical Input output waveform for digital circuits Input Pulse Output Waveform Non Inverted

Kishore Acharya12 Typical Input output waveform for digital circuits at the maximum limit Input Pulse Output Waveform Non Inverted At the maximum operating frequency output pulse is not square any more and it barely touches the input pulse.

Kishore Acharya13 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 Acharya14 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 Acharya15 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