User Guide

Contents
vi
Creating and editing models 85Chapter 4
Chapter overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
What are models? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
Models defined as model parameter sets . . . . . . . . . . . . . . 87
Models defined as subcircuit netlists . . . . . . . . . . . . . . . . 87
How are models organized? . . . . . . . . . . . . . . . . . . . . . . . . . 88
Model libraries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
Model library configuration . . . . . . . . . . . . . . . . . . . . . . . 89
Global vs. design models and libraries . . . . . . . . . . . . . . . . . 89
Nested model libraries . . . . . . . . . . . . . . . . . . . . . . . . . . 90
OrCAD-provided models . . . . . . . . . . . . . . . . . . . . . . . . . 90
Tools to create and edit models . . . . . . . . . . . . . . . . . . . . . . . . 91
Ways to create and edit models . . . . . . . . . . . . . . . . . . . . . . . . 92
Using the Model Editor to
edit models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
Ways to use the Model Editor . . . . . . . . . . . . . . . . . . . . . . 94
Model Editor-supported device types . . . . . . . . . . . . . . . . . . 95
Ways To Characterize Models . . . . . . . . . . . . . . . . . . . . . . 96
Creating models from data sheet information . . . . . . . . . . . 96
Analyzing the effect of model parameters
on device characteristics . . . . . . . . . . . . . . . . . . . 97
How to fit models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
Running the Model Editor alone . . . . . . . . . . . . . . . . . . . . . 99
Starting the Model Editor . . . . . . . . . . . . . . . . . . . . . . . 99
Enabling and disabling automatic part creation . . . . . . . . . . 100
Saving global models (and parts) . . . . . . . . . . . . . . . . . . 100
Running the Model Editor from the schematic page editor . . . . . . 101
What is an instance model? . . . . . . . . . . . . . . . . . . . . . . 101
Starting the Model Editor . . . . . . . . . . . . . . . . . . . . . . . 102
Saving design models . . . . . . . . . . . . . . . . . . . . . . . . . 102
What happens if you don’t save the instance model . . . . . . . . 103
The Model Editor tutorial . . . . . . . . . . . . . . . . . . . . . . . . . 104
Creating the half-wave rectifier design . . . . . . . . . . . . . . . 104
Using the Model Editor to edit the D1 diode model . . . . . . . . 105
Entering data sheet information . . . . . . . . . . . . . . . . . . . 105
Extracting model parameters . . . . . . . . . . . . . . . . . . . . . 107
Adding curves for more than one temperature . . . . . . . . . . 108
Completing the model definition . . . . . . . . . . . . . . . . . . 109
Editing model text . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110
Editing .MODEL definitions . . . . . . . . . . . . . . . . . . . . . 110
Editing .SUBCKT definitions . . . . . . . . . . . . . . . . . . . . . 111
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