User Guide

Chapter 12 Monte Carlo and sensitivity/worst-case analyses
290
runs, saving the DC analysis output from those five
runs.
PSpice starts by running all of the analyses enabled in the
Simulation Settings dialog box with all parameters set to
their nominal values.
However, with Monte Carlo enabled, PSpice saves the DC
sweep analysis results for later reference and comparison.
After the nominal analyses are finished, PSpice performs
the additional specified analysis runs (in this example, DC
sweep).
Subsequent runs use the same analysis specification as the
nominal run with one major exception: instead of using
the nominal parameter values, the tolerances are applied
to set new parameter values and thus, new part values.
There is a trade-off in choosing the number of Monte
Carlo runs. More runs provide better statistics, but they
require more time. The amount of time scales directly with
the number of runs: 20 transient analyses take 20 times as
long as one transient analysis. During Monte Carlo runs,
the PSpice status display includes the current run number
and the total number of runs left.
Figure 75 Monte Carlo analysis setup for EXAMPLE.DSN.
PSpice o
ff
ers a
f
aci
l
ity to generate
histograms of data derived from Monte
Carlo waveform families through the
performance analysis feature.
For information about performance
analysis, see RLC filter example
on
page 11-274.
For information about histograms, see
Creating histograms
on
page 12-303.
Pspug.book Page 290 Wednesday, November 11, 1998 1:14 PM