Fully Functional Nonlinear Table-Based HBT Model With Explicit Thermal Feedback

A fully functional table-based nonlinear model of the heterojunction bipolar transistor (HBT) is presented which includes explicit thermal feedback. The model uses four table-based nonlinear functions: I_c, Q_c, V_be, and Q_b, all defined versus I_b and V_ce by using a nonuniform bias grid. Thermal modeling (self-biasing and environment temperature dependence, T_a) is done by linearly mapping the table-based current functions versus T_a coupled with explicit thermal feedback. Four table-based nonlinear coefficients are required to accurately predict the device behavior versus temperature. Excellent results have been obtained under dc, small, and large signal excitations for InGaP/GaAs HBTs in the range 10degC to 110degC.