User Guide

Settin
g
Up the Circuit File C
-3
Settin
g
Up the Circuit
File
To use the PSpice Optimizer to optimize a desi
g
n
defined as a netlist
1
Decide on the design parameters you want the optimizer to
vary.
2
Place parameter definitions (.PARAM) in a separate
parameters file (
.par).
3
Include the parameters file in the circuit file using the .INC
command.
4
Replace component values that are dependent on the
parameters with expressions.
All of these steps use standard PSpice syntax; see your PSpice
user’s guide for details. The following section explains why you
need to set up a separate parameters file, and how to do it (steps
2 and 3 above).
The parameters file (.PAR)
When optimizing, the
PSpice Optimizer uses a separate parameters file to track
changes to parameter values with each iteration. This file
contains nothing but PSpice parameter definitions reflecting the
last-used values.
The optimizer automatically looks for a file with the name
circuit_file_name .par.
Example: If the design is contained in
myamp.cir, the
optimizer writes updated parameter definitions to
myamp.par.
To create a parameters file for a desi
g
n
1
Activate any text editor.
2
For each parameter in the circuit, enter a line using the
syntax:
.PARAM
parameter
_
name
=
starting
_
value
3
Save the file as
circuit_file_name .par.