On the Number of Noise Parameters for Analyses of Circuits With MOSFETs

The inequality relating F_min and Lange invariant N for any noisy linear two-port network has been known since the 1980s. However, the applicability of this inequality to MOSFETs is not discussed in the literature, and thus, this inequality is not normally treated in analyses and designs of circuits based on MOSFETs. This work shows that by using N, the number of noise parameters required to model high-frequency noise of intrinsic MOSFETs can be reduced by one. This reduction in the noise parameters simplifies the noise correlation matrices, which leads to simpler noise factor expressions. A new set of noise correlation matrices and noise factor expressions is presented. These are expected to ease circuit optimizations of low-noise amplifiers and other circuits based on intrinsic MOSFET models.