HIGH-FREQUENCY NONLINEARITY ANALYSIS OF COMMON-EMITTER AND DIFFERENTIAL-PAIR TRANSCONDUCTANCE STAGES

Equations describing the high-frequency nonlinear behavior of common-e mitter and differential-pair transconductance stages are derived, The equations show that transconductance stages using inductive degenerati on are more linear than those using capacitive or resistive degenerati on, and that the common-emitter transconductance stages are more linea r than the differential-pair transconductance stages with the same bia s current and transconductance. The nonlinearity equations can also be used to explain the class AB behavior of the common-emitter transcond uctance stage with inductive degeneration.