RF Linearity of SiGe HBT: Physics, Compact Modeling Using Mextram 505 and X-Parameter Based Measurements

We review linearity of SiGe HBTs, from physics to RF measurements using X-parameter capable NVNA, to compact modeling using Mextram 505, an industry standard model. New models of high injection depletion capacitance and avalanche enable accurate linearity sweet spot modeling. Source distortion and port mismatches can be accounted for using X-parameters to significantly improve measurement accuracy, which also greatly simplifies circuit setup in modeling.