2.6.1 Behavioral Models

In Chapter 2.3 we implemented small-signal equivalent circuits for semiconductor devices as subcircuit objects composed of the available linear circuit primitives. We cannot use this approach to model the electrical characteristics of nonlinear elements, such as diodes or transistors. However, particularly for nonlinear circuit analysis, Analog Insydes provides special support for modeling arbitrary circuit element characteristics by specifying device equations directly.

Models which are based on sets of mathematical equations describing the behavior of a circuit element or an analog building block are frequently called (analog) behavioral models, or ABMs. A behavioral model is similar to a subcircuit object in that it constitutes a box which is connected to a circuit through electrical ports. As indicated above, the difference is that the interior of a behavioral model box is implemented in terms of symbolic equations rather than a netlist. With Analog Insydes' behavioral modeling capabilities you can model a large variety of nonlinear element characteristics. You can then use the function CircuitEquations, with which you are already familiar, to set up symbolic systems of nonlinear modified nodal or sparse tableau equations.