1. The George Washington University School of Engineering and Applied Science Department of Electrical and Computer Engineering Circuit Design Verification Using PSpice (Cadence/OrCAD) Jason Woytowich (former GTA) Farid Hassani (ECE GTA)

2. Outline Introduction General Process Basic Example – Half-Wave Rectifier Advanced Example – Demodulation

3. Introduction SPICE is a general purpose circuit simulation language that performs non-linear DC, transient and linear steady state AC analysis. SPICE models: –Linear circuit elements of resistance, capacitance, inductance, independent and dependent current and voltage sources –Four of the most common nonlinear semiconductor devices (Diodes, BJTs, JFETs and MOSFETs) –Other useful circuit elements including transmission lines and mutual inductance

4. Cadence PSpice OrCAD bought MicroSim and its PSpice products in January 1998. Cadence bought OrCAD in August 1999.

5. General Process 1. Design your circuit 2. Draw your circuit 3. Specify your analysis 4. Run the simulation 5. Analyze the output 6. Go back to 1, 2 or 3 as needed

6. Starting Cadence

8. Start a New Project

9. Select Project Options

10. Project Types Only two types are of immediate concern 1.Analog or Mixed A/D -The project is meant for simulation. This is for design verification. 2.Schematic -This option is used for PCB design. It is only used to generate a netlist. We will use this for your Board Fabrication Details.

11. Create a Blank Project

12. Schematic

13. Place Parts

14. Placing Parts

15. Changing Values

16. Completed Half-Wave Rectifier

17. Create a Simulation Profile

18. Set the Simulation Parameters

19. Simulation Types DC / OpPoint – All AC sources are zeroed (Shorted/Opened) Transient – View with respect to time DC Sweep – View the response to a range of DC inputs AC Sweep – View the response to a range of frequencies

20. Run the Simulation Press the blue arrow in the toolbar on the top.

21. Select Output

22. Output 1

23. More Output

24. Output 2

25. A More Complicated Example Input – 5Vpeak, 2kHz Sine Wave pulsed for 5ms ever 20ms starting 1ms and an output impedence of 1kOhm The input passes through a simple BPF with a gain of 1. The output of the BPF is rectified and passed through an RC filter with a time constant of 0.5ms. Put the output across a 1Meg Ohm resistor.

26. Using Heirarchy You can break your Pspice design into modules. These modules can be linked together at the top level.

27. Signal Source VDC VSI N VPULS E MULT – From ABM

28. Band Pass Filter LM741 from OPAMP Notice the power supply connections Input Port Output Port

29. Rectifier

30. Top Level

31. Simulation Is the output what you expect?

32. Simulation

33. Perform Your Own Simulations This presentation was adapted from a presentation by Farid Hassani