A Theory of High-Frequency Distortion in Bipolar Transistors

High-frequency distortion in bipolar transistors is examined by using the charge-control approach of Poon and Narayanan to connect the device’s distortion behavior to its “loaded” unity–current–gain frequency (^ ). The resulting expressions for the distortion reveal considerable information on its frequency and bias dependence. Points on the ^ versus collector current curve yielding optimum distortion performance are identified and interpreted in terms of current cancellation. Both secondand third-order distortion are considered, and the results are validated by both simulation and experiment.