Customizing IC-CAP

Implementing New Model Equations

Test new models in IC-CAP by defining them in the form of a series of equations in a Program Transform or a User C function. Implement a complete model or subset of a model in this way. To define a model, calculate the node current or currents, using the node voltages and model parameters. An example of this is the BJT_dc_model function in the userc.c file.

To simulate a model defined in this manner, execute the Transform. After the model is fully tested, implement it in the circuit simulator.

Implementing New Extractions

You can implement new extraction algorithms by using the Program2 or Program Transform. This Transform provides a powerful method for accessing measured data and calculating model parameters from this data. IC-CAP also includes a number of functions that greatly simplify this operation. For example, a number of rather tedious operations are replaced by functions that calculate derivatives, or least-squares fit to the data. You can create new extractions simply by assembling a series of existing IC-CAP functions.

C functions can be used to increase both the performance and functionality of the above operations. Most of IC-CAP's existing extraction functions are implemented in the C language.

The optimizer can also be used for extracting model parameters. To do this, define Optimize Transforms for the Setups and specify in them the model parameters to be optimized. For further information, refer to Chapter 7, "Optimizing."