User`s guide

Monte Carlo Analysis 13
-13
Usin
g
resistors with models
To explore the effects of manufacturing tolerances on the
behavior of this circuit, you will set device (DEV) and (LOT)
tolerances on the model parameters for resistors R1, R2, R3, and
R4 in a later step (see page 13-14
). This means you need to use
resistor symbols that have model associations.
Because R symbols do not have an associated model (and
therefore no model parameters), change the resistor symbols to
Rbreak symbols which do have a a model.
To replace R1, R2, R3, and R4 with the RBREAK
s
y
mbol
1
Click R1 to select it.
2
S+click R2, R3, and R4 to add them to the selection
set.
3
From the Edit menu, select Replace.
4
In the Replacement text box, type
Rbreak.
5
Choose the Selected Parts Only option.
6
Click OK.
Notice that the reference designator changes to the next
consecutive set of identifiers.
7
To change each resistor’s reference designator back to its
original identifier, do the following for each resistor that
you just replaced:
a
Double-click the resistor’s reference designator label.
b
Type in its original identifier as shown in Figure 13-5
on page 13-10.
c
Click OK.
When PSpice A/D runs a Monte
Carlo analysis, it uses tolerance
values to determine how to vary
model parameters durin
g
the
simulation.