Characterization of low VAR bipolar transistors using a revised SPICE simulator

Abstract

The approximation of the Gummel-Poon base width modulation term, q1, that is implemented in conventional versions of SPICE, is discussed. The impact of the approximation of the characterization of low VAR bipolar transistors is described. Comparisons of simulated to measured curves demonstrate the improved accuracy which results from using the unapproximated q1 term. Use of the unapproximated q1 term produces physically meaningful Early voltage parameters and improved simulation accuracy.<>