Models used in Simulation

In the PSpice for TI solution, the models are accessed from the libraries in a predefined order. With the PSpice for TI installation, you get two kinds of model libraries:

• TI libraries
• Cadence-supplied libraries

Both these are pre-installed libraries. You can configure model libraries at simulation profile level, design-level, and custom-global-level (using the Simulation Setting dialog box).

Order of Access

PSpice for TI accesses the models that are used for simulation in the following order:

1. Models from libraries added to profile
2. Models from libraries added to design
3. Models from libraries installed with PSpice for TI (globally configured)
   1. TI models installed with PSpice for TI
   2. Cadence-supplied models installed with PSpice for TI

Order of Precedence

PSpice for TI follows the following precedence for models:

1. Models referred directly on schematic or design: If PSpice for TI finds a model with multiple definition in the configured libraries, then models are accessed as per the order explained above.
2. Model referred by a subcircuit model definition: For the models that are referred to from a specific subcircuit model definition, PSpice for TI assigns highest precedence to model definition found in same library file. If models or subcircuits are not found in the current library, then they are searched from other libraries as per the order of access explained above.

Example

If a subcircuit, TOP_B in a library file LIBRARY_B refers to another model/subcircuit, then this model/subcircuit will first be searched in the current library where TOP_B is defined, that is LIBRARY_B.

On a schematic, if you have placed the following parts:

• Subcircuit, TOP_B 
  • Which refers to subcircuit, SUB_TOP_B
    • Where SUB_TOP_B refers to model, MOSFET_M
• Model, DIODE_M 

The order in which libraries are indexed is as follows:

1. LIBRARY_A, has the following definition:
   • SUB_TOP_B (subcircuit)
   • DIODE_M (model)
   • MOSFET_M (model)
2. LIBRARY_B, which has the following definition:
   • TOP_B (subcircuit)
   • SUB_TOP_B (subcircuit)
   • DIODE_M (model)

Now on simulation, the models are picked in the following manner:

• TOP_B gets picked from LIBRARY_B
  • SUB_TOP_B gets picked from LIBRARY_B
    •  MOSFET_M gets picked from LIBRARY_A
• DIODE_M gets picked from LIBRARY_A

The same behavior is applicable for parameter statements defined in the library file.