A CHARGE CONSERVING CAPACITANCE MODEL FOR GAAS-MESFETS FOR CAD APPLICATIONS

A charge conserving capacitance model for GaAs MESFETs for Computer Ai ded Design (CAD) applications is presented. Simple analytical expressi ons for node charges were developed by integrating the sheet charge de nsity over the gate length, which guarantees the charge conservation. The capacitances were defined by taking derivatives of the charges wit h respect to terminal voltages at the three nodes. The resulting, so-c alled transcapacitances are nonreciprocal in nature. Thus, we have def ined a new equivalent circuit based on a total of nine transcapacitanc es, which can be organized as a 3 x 3 matrix. The model is valid both above and below threshold.