PSPICE

SPICE = Simulated Program with Integrated Circuit Emphasis Virtual breadboard to test/design circuits Use for: (1) Transient Analysis: voltage & current vs. time (2) DC Analysis: such as varying voltage (3) AC Analysis: frequency response

Getting PSPICE

Download orCAD from EE dept. web page: http : // electrical.sdsu.edu/software.html

License info. Included in instruction file from same page (works for either 16.2 or 16.3) You need to install at least 'Capture' and 'Pspice' Might have problems if using Windows 7.

Steps to using Pspice(1) Draw circuit (using Capture) (2) Simulate (using Pspice) (3) Analyze (using Probe) NOTE: All of these steps can be done from Capture, since Pspice and probes are included in a toolbar.

Getting Started

Cadence Release 16.3 OrCAD Capture

Create a New Project

File New Project Analog or Mixed A/D Create a blank project (you will have to add parts libraries)

Software Layout

Add Parts Button

You might need to add the following libraries: ANALOG, SOURCE, OPAMP (next slide) Make sure they're highlighted so you can search for parts in them

Add libraries

Choose multiple libraries if you want (use ctrl)

Add Parts

Make sure libraries selected Type in search box Select part using 'Enter' key or 'Place Part' icon Click on schematic to place part Place multiple copies ('ESC' key to stop placing part)

Don't forget ground

Click ground symbol on toolbar

Change Circuit Values (like R,L,C)

By double-clicking on value, not component name Remember unit symbols (not case sensitive) example: to enter R = 1 k 1000 or 1e3 or 1k1e-15 1e-12 1e-9 1e-6 1e-3 f p n u m femto pico nano micro milli 1e12 1e9 1e6 1e3 T G MEG k Tera Giga Mega kilo

Examples

DC bias DC transient AC analysis frequency response DC analysis

DC Bias Example

After building circuit, create 'New Simulation Profile'

DC Bias Example (cont)

Name simulation, Select 'Bias Point', Apply. Click 'Run'

DC Bias Example (cont)

DC Transient Example

Create a circuit with initial conditions (next page)

DC Transient Example (cont)

Click on part to select it, right-click to access menu Initial conditions (IC) can be accessed in properties

DC Transient Example (cont)

Scroll through list until you find IC, set value

DC Transient Example (cont)

Create 'New Simulation Profile' Change end time & step size Make sure to click 'Apply'

DC Transient Example (cont)

Click 'Run', add probes Types of probes: voltage, voltage differential, current, power Note: voltage probes can be placed anywhere, but current probes must be placed on part edges

DC Transient Example (cont)

The results window will automatically come up

AC Analysis- freq. response (example)

Build circuit using sinusoidal voltage source (VSIN) Make sure input voltage level is 1V Need to add special probes for voltage in db and phase (next slide)

AC Analysis- freq. response (example)

Add special probes using: Pspice Markers Advanced

AC Analysis- freq. response (example)

Create 'New Simulation Profile' Change analysis type & specify start/stop frequency & number of frequency points (for Bode plot use Logarithmic freq. scale)

AC Analysis- freq. response (example)

Initially both signals will be on the same plot (not very useful)

AC Analysis- freq. response (example)

Right-click on the amplitude response (red one) & copy to clipboard. Then 'hide trace'.

AC Analysis- freq. response (example)

Add a new plot: Plot Add Plot to Window Click in blank plot and paste (ctrl-v)

AC Analysis- freq. response (example)

Top: Voltage Magnitude (dB) Bottom: Voltage Phase (degrees)

DC Analysis Example

Simple voltage divider circuit. Simulate changing input DC voltage.

DC Analysis Example (cont)

Create 'New Simulation Profile' Choose 'DC Sweep', specify start/stop voltages and increment Specify source 'Name' (make sure it matches the name on your circuit). Apply changes

DC Analysis Example (cont)

Click 'Run' and view results.

Conclusion

Pspice provides a quick and easy way to test your circuit designs (compared to actually building them). You may not end up using Pspice in your Engineering career, but you will definitely use simulation software of some sort (and once you figure out how to use one, the rest are easier to learn).