User Guide

Chapter 1 Things you need to know
12
You can create these files using OrCAD programs like the
Stimulus Editor and the Model Editor. These programs
automate file generation and provide graphical ways to
verify the data. You can also use the Model Text view in
the Model Editor (or another text editor like Notepad) to
enter the data manually.
Model library
A model library is a file that contains the electrical
definition of one or more parts. PSpice uses this
information to determine how a part will respond to
different electrical inputs.
These definitions take the form of either a:
• model parameter set, which defines the behavior of a
part by fine-tuning the underlying model built into
PSpice, or
• subcircuit netlist, which describes the structure and
function of the part by interconnecting other parts and
primitives.
The most commonly used models are available in the
OrCAD model libraries shipped with your programs. The
model library names have a .LIB extension.
If needed, however, you can create your own models and
libraries, either:
• manually using the Model Text view in the Model
Editor (or another text editor like Notepad), or
•
automatically using the Model Editor.
A su
b
circuit, sometimes ca
ll
e
d
a
macromodel, is analogous to a
procedure call in a software programming
language.
See What is the Model Editor?
on page 1-10 for a description.
Pspug.book Page 12 Wednesday, November 11, 1998 1:14 PM