A Spice Model for Enhancement-and Depletion-Mode GaAs FET´s

An improved model for the GaAs MESFET has been implemented in the source code of the circuit-simulation program SPICE. New features include 1) an accurate model for the Schottky barrier, which allows simulation of both enhancement- and depletion-mode devices; 2) detailed modeling of the nonlinear gate-source and gate-drain capacitance; and 3) a user-specifiable value for the exponent in the expression for the dependence of the dc drain current upon the gate-source voltage. Also discussed are some important points concerning the charge-voltage equations that must accompany the new model´s capacitance-voltage equations within SPICE. The new GaAs FET SPICE model is believed to be the most comprehensive one available to date in the public domain.