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PSpice® User’s Guide
includes PSpice A/D, PSpice A/D Basics, and PSpice
Product Version 10.0
June 2003

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PSpice User's Guide
June 2003 3 Product Version 10.0
Before you begin. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Welcome . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
How to use this guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Symbols and conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Related documentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
What this user’s guide covers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
PSpice A/D overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
PSpice A/D Basics overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
PSpice overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
PSpice Advanced Analysis overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
If you don’t have the standard PSpice A/D package . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Comparison of the different versions of PSpice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
If you have PSpice A/D Lite . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Minimum hardware requirements for running PSpice: . . . . . . . . . . . . . . . . . . . . . . . . 29
Part one: Simulation primer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
1
Things you need to know . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Chapter overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
What is PSpice A/D? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Analyses you can run with PSpice A/D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Basic analyses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Advanced multi-run analyses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Analyzing waveforms with PSpice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
What is waveform analysis? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Using PSpice with other programs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Using OrCAD Capture to prepare for simulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
What is the PSpice Stimulus Editor? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
What is the PSpice Model Editor? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Files needed for simulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Files that OrCAD Capture generates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Contents

PSpice User's Guide
June 2003 4 Product Version 10.0
Other files that you can configure for simulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Files that PSpice generates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
New directory structure for analog projects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
How are files configured at the design level maintained in the new directory structure for
analog projects? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
How are files configured at the profile level maintained in the new directory structure for
analog projects? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
What happens when I convert an analog project that uses a design from another project
or from another location? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
What should I do if the schematic for a converted analog project uses FILESTIMn parts
from the SOURCE library? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
2
Simulation examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
Chapter overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
Example circuit creation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
Finding out more about setting up your design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
Running PSpice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
Performing a bias point analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
Using the simulation output file . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
Finding out more about bias point calculations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
DC sweep analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
Setting up and running a DC sweep analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
Displaying DC analysis results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
Finding out more about DC sweep analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
Transient analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
Finding out more about transient analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
AC sweep analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
Setting up and running an AC sweep analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
AC sweep analysis results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
Finding out more about AC sweep and noise analysis . . . . . . . . . . . . . . . . . . . . . . . . 88
Parametric analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
Setting up and running the parametric analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
Analyzing waveform families . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
Finding out more about parametric analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
Performance analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97

PSpice User's Guide
June 2003 5 Product Version 10.0
Finding out more about performance analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
Part two: Design entry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
3
Preparing a design for simulation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
Chapter overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
Checklist for simulation setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104
Typical simulation setup steps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104
Advanced design entry and simulation setup steps . . . . . . . . . . . . . . . . . . . . . . . . . 105
When netlisting fails or the simulation does not start . . . . . . . . . . . . . . . . . . . . . . . . 106
Using parts that you can simulate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
Vendor-supplied parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108
Passive parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
Breakout parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114
Behavioral parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116
Specifying values for part properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116
Using global parameters and expressions for values . . . . . . . . . . . . . . . . . . . . . . . . . . 117
Global parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117
Expressions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
Defining power supplies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126
For the analog portion of your circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126
For A/D interfaces in mixed-signal circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126
Defining stimuli . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128
Analog stimuli . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128
Digital stimuli . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
Things to watch for . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133
Unmodeled parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133
Unconfigured model, stimulus, or include files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137
Unmodeled pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138
Missing ground . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139
Missing DC path to ground . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139