User Guide

Chapter 8 Preparing Your Design for Simulation
256
Handling Unmodeled Pins
Parts that have some pins that are not modeled, will
appear broken when placed on the schematic. To see an
example of this, place an instance of the PM-741 part from
the “opamp.slb” symbol library. The OS1 and OS2 pins
are not modeled, so only the +, -, V+, V-, and OUT pins are
netlisted for simulation.
For the simulator, these pins appear as a large resistor
connected to the ground.
Double-click the part to display the Attribute Editing
dialog box. Note that the TEMPLATE attribute for the part
only calls out the +, -, V+, V-, and OUT pins. The OS1 and
OS2 pins are not called out in the TEMPLATE because those
two pins are not modeled in the simulation model for the
PM-741 part. You can view the simulation model
definition for the PM-741 part from PSpice Schematics.
Viewing a simulation model for a part
1 Click the part to select it.
2 From the Edit menu, select Model.
3 Click Edit Instance Model (Text) to display the
Schematics Model Editor and view an instance of the
simulation model definition.
4 Click Cancel to exit the Model Editor without saving.