result becomes too large then more complex and more ac- curate models have to be selected. For this purpose Ana- log Insydes offers a flexible subcircuit and model management. An example for the description of a more detailed BJT small-signal equivalent circuit is given in Figure 4. The following strategy is now pursued to extract the pa- rameters of the macro model from the transistor topology: The circuit under examination is first simulated numeri- cally, e.g. with SPICE. From the simulator output file the operating-point information and the small-signal parame- ters of the transistors are extracted and passed to Analog Insydes (AI). Model accuracy in AI may be chosen rang- ing from a simple hybrid BJT model up to the complete small-signal equivalent circuit as used by SPICE. In this case, the operating frequency of the circuit is low enough to allow for neglecting parasitic capacitances, so a static small-signal BJT model is selected. The conversion from the numerical simulation results to the parameter values of different transistor models is per-