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.