PSPICE Tutorial

Part 1: Installing, Project creation, Schematic Circuit set-up, Edit

PSpice Model

When installing Orcad Lite 9.2

In Orcad Lite Set Up - Enable both Capture and PSPICE!

Let’s simulate the discrete CS amplifier example:

Phase 1: Project Creation Schematic Creation Components Libraries Configuration Components Layout Wiring Components Values Simulation Profile Creation

Creating New Project

• File: New Project• In “New Project” window – project name is

arbitrary, note “Using” and “Location” entries.

Two windows: Project Manager and Schematic

Project Manager operations:

• Enable by clicking on (+), and it turns to (-).• Enable both project and Schematic.• Right-click on Schematic1 to rename it.

Clicking on the Schematic page brings up the right toolbar:

• Most frequently used icons:

• First – Place Part• Second – Place Wire• Third – Place net

alias (i.e. node labeling)

• Eighth – Place Ground

Click “Place Part” icon Click “Add Library” In “Browse File” box right-click-drag to select all

libraries Click “Select” Finally click “Cancel” to leave this mode

This process needs to be done only once per project. Libraries are then configured for all schematics.

Only one ground type will do!

Click on “Place Ground” Click “Add Libraries” Open “PSpice” folder Open “Source” library Select “0” Click “Cancel”

Let’s start by placing an NMOS in the schematic:

Click “Place Part” Select “Breakout” library Scroll to and select “MbreakN” (for a 4-terminal NMOS). For PMOS take MbreakP.

Click “OK” to place the part. Right-click and then “End Mode” to stop parts production.

Placing all the parts:

R,C from “Analog” library; VDC,VSIN from “Source” library; “0” from the “Ground” library.

Click-select part to move it, or after right-clicking to rotate it

Wiring the components -1

Click “Place Wire” Drag cross-hair to a component terminal Left-click and let go Drag to next terminal and left-click to establish wire

(Can stop mid-way if need to route wire by 900 more than once)

Wiring the components - 2

Red dots show up when two wires meet electrically. Red dots in unwanted or odd places may indicate spurious wires that need to be removed (i.e. selected and deleted)

(If you short circuit Source to Substrate too close to the component you may not be able to undo it)

Double-click on component’s value to change it

(In PSPICE 1MΩ is written “1meg”. “1M” = 1 milli-Ohm)

Adding Node Labels

• Click on N1 icon Type name, such as “in” or “out”, etc Move label frame so that it touches the respective wire.

• By clicking on component’s name (say “R1”), can change its name to, say, “RG1”.

Transistor’s parameters -1

Click-select NMOS. Then Edit: PSpice Model Model Editor opens up.

Transistor’s Parameters - 2

• First, create a new name for the component:• Place cursor to left of * and put in some

descriptive name.• Don’t save yet.

Transistor’s Parameters - 3

• Next, type in the SPICE code (in the right field)• SPICE code starts with + symbol. No spaces.• Full list of permissible parameters can be found in

the “PSPICE Reference Manual” (one of the on-screen documentation files that came on your CD).

Transistor’s Parameters - 4

• Note that KP’s units are [A/V2]!• Units of W,L are [meter]. Therefore, L=4u means

L=4μm.• When you are done typing the code, Save.• Before leaving Model Editor, you may want to

display the parameters on the circuit schematics.

Displaying Transistor’s Parameters – Method 1

• Return to the Schematic page.• In upper toolbar click “Place”, and select “Text”.• A “Text Edit” window opens up. Type the

MOSFET parameters “LEVEL=1, VTO=1V,…”. You may press Ctrl+Enter to start text new lines, for a more compact presentation.

• Place text block somewhere near transistor. You may also place a line (using Place:Line) to connect textbox to the right transistor.

Displaying Transistor’s Parameters – Method 2

• Return to the Schematic page.• Double-click on the MbreakN component

to open a Property Editor.• Click “Add New Column”, and type

“LEVEL”, add a value “1”. Select both cells and click “Display”. Select “Name and Value”.

• Repeat for each parameter.

Resulting Displays