Noise modelling for broadband amplifier design

We consider in this paper the derivation of input equivalent noise voltages and currents for both feedback and nonfeedback amplifier configurations. In the case of feedback amplifiers, a greatly simplified, approximate analysis is utilised and the accuracy of the approximation established. For low-noise amplifiers, a systematic design approach based on input equivalent noise sources is outlined. The relationship between the dual-input equivalent noise voltage and current sources is also established and a design example presented.