Asymptotic transconductance design of transistor amplifiers

Problems associated with stabilizing and desensitizing the voltage gain, input impedance, and interstage impedances of transistor amplifiers against variations in transistor parameters are discussed. In the systematic pursuit of these objectives, voltage gain and impedances are found to approach simple asymptotic values, for which the error fraction may be precisely defined. The sensitivity of these error fractions to transistor parameter variations also may be accurately stated. Development of this concept will make use of the short-circuit admittance parameters, or y parameters, of the transistors. Conclusions, however, will be stated in terms of minimum Ft, minimum low-frequency beta, and a knowledge of the d-c operating conditions of the transistors.