Editing a Model

Many of the models supplied are in text format. It is easy to edit any model in this format but, it must be remembered that, with very few exceptions, the models list model parameters, extracted from the model datasheet and not, directly the datasheet parameters.

If a Part in the Schematic references a PSpice model, selecting the Part and right-click>Edit PSpice Model will start the Model Editor with a local library for the project containing a copy of the model from the library.

Model Editor

The Model Editor provides a means to edit and create Models. The Model Editor can create Models for: Diodes, Bipolar transistors, Magnetic cores, IGBTs, Junction FETs, MOSFETs, Voltage Comparators, Voltage Regulators, Voltage References, Darlington transistors.

The Model Editor can create Models from graphical input extracted from datasheets but note that, especially for smaller geometry MOSFETs, extracting models from the graphical input may not result in a sufficiently accurate model since the required model parameters cannot be created in this manner – they can only be added as numerical parameters.

The Model Editor can be used to create a Schematic Library. The PSpice intrinsic parts will be created with the appropriate graphics but sub-circuits will be created as a rectangle with Pins for the interface nodes.

Referenced Model

The model referenced by a Part in the Schematic is determined by the Implementation Property – not required for any of the intrinsic PSpice Models – and this is typically not a displayed property. For the Breakout parts, Dbreak, Kbreak and so on, the Implementation property is displayed, rather than the Value.

Library Indexing

Storing the Models in text format doesn’t represent a very efficient mechanism for searching for Models in the libraries so, when a new library is added, or the Model library is updated, an index file is created, or updated and the simulator searches the index files to find the required Models efficiently. The index for the provided libraries is created during the product installation process.

Adding Model Libraries

The Model Libraries are configured through the Simulation Profile. Libraries can be added as Global, to the Design, or to the Simulation Profile. To the Design is probably the best place to add Model Libraries since this will remain valid if an updated release is used. Global Libraries will need to be restored if the product release is updated. Adding Model libraries to specific Simulation Profiles can be useful if experimenting with alternative Models.

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