User`s guide

How Are Models Or
g
anized? 4
-5
Model Librar
y
Confi
g
uration
PSpice A/D searches model libraries for the model names
specified by the MODEL attribute value on symbols in your
schematic. These are the model definitions that PSpice A/D uses
to simulate your circuit.
For PSpice A/D to know where to look for these model
definitions, you must configure the libraries. This means:
• Specifying the directory path or paths to the model libraries.
• Naming each model library that PSpice A/D should search
and listing them in the needed search order.
• Assigning global or local scope to the model library.
Global vs. Local Models and
Libraries
Model libraries and the models they contain have either local or
global application to your designs.
Local models
Local models apply to one design. The
schematic editor automatically creates a local model whenever
you modify the model definition for a part instance on your
schematic. You can also create models externally and then
manually configure the new libraries for a specific design.
Global models
Global models are available to all designs
you might create. The symbol editor automatically creates a
global model whenever you create a symbol with a new model
definition. The Parts utility also creates global models. You can
also create models externally and then manually configure the
new libraries for use in all designs.
To optimize the search, PSpice
A/D uses indexes. To find out
more about this and how to add,
delete, and rearran
g
e confi
g
ured
libraries, see
Configuring Model
Libraries on page 4-41.
To find out how to chan
g
e the
local and
g
lobal confi
g
uration of
model libraries, see
Changing
Local and Global Scope on
page 4-45.
Example usa
g
e: To set up
device and lot tolerances on the
model parameters for a
particular part instance when
runnin
g
a Monte Carlo or
sensitivity/worst-case analysis.
PSpice A/D searches local
libraries before
g
lobal libraries.
To find out more, see
Changing
Model Library Search Order on
page 4-45.