Symbolically defined empirical large-signal model for HBTs compared to the Gummel-Poon model

摘要

An empirical symbolically defined nonlinear model, which accounts for several important effects in HBTs, is used in the large signal characterization of planar InGaP/GaAs HBTs. The model is designed to predict accurately the DC and RF characteristics based on an empirical equation. In order to assess the validity and the accuracy of the proposed model, a seven port symbolically defined device (SDD) based on the equation is constructed in an Agilent ADS circuit simulator for a 2/spl times/20 /spl mu/m/sup 2/ emitter area transistor and compared to measurements as well as to the Spice Gummel-Poon model in DC, in small signal and in large signal modes. From this comparison, one can conclude that, for the device tested, the SDD empirical model gives better agreement with measurements than the Spice Gummel-Poon model, for all modes of operation.