Graphical design of multistage feedback amplifiers

This paper presents a semi-analytical graphical technique for stabilizing an initial unstable feedback amplifier by the addition of passive circuit components. The stabilized amplifier can be chosen to have a Butterworth, Bessel, or critically damped transfer function, as desired. Its bandwidth is restricted to somewhat less than the transistor \´s so that the transistors can be adequately represented by a hybrid- or other rational model. The technique is applied to the design of a low-noise fiber-optic receiver front end capable of driving a load, with the main feedback loop around the whole amplifier.