Miller theorem for weakly nonlinear feedback circuits and application to CE amplifier

The paper presents the derivation of Miller formulas for weakly nonlinear feedback networks. The expressions found are simple and compact and constitute a generalization of the well-known linear case. As an application example, the formulas are applied to a common-emitter amplifier to straightforwardly derive the closed-form expressions of second- and third-harmonic distortion factors. The results found, validated by Spectre simulations with a VBIC bipolar model, allow to understand in depth the contribution of each nonlinear element. Index Terms--Amplifiers, analog circuits, harmonic distortion, Miller theorem, nonlinear network analysis.