Utmost IV pulls SPICE parameters from the TCAD flow or from your measured data, then optimizes them across temperatures, wafers, die and devices. Fit DC, capacitance and S-parameter data alongside extracted values such as Vt, Idsat and ft. Build hierarchical macromodels, and tune device-model and netlist parameters together. Extraction and simulation both cover three GaN compact models.
In SmartSpice, Circuit Rubberband tunes transient behavior against time-based data: gate charge and the Miller plateau, and reverse recovery (trr and Qrr).