Miller’s Wrong Half-Plane Zero [Shop Talk: What you didn’t Learn in School]

Abstract

The right half-plane (RHP) zero associated with Miller frequency compensation in feedback loops is well known. But much of what we've learned about it is incomplete, misleading and -occasionally- wrong. This column explores the fundamental nature of the RHP zero and the circuit techniques that have evolved to deal with it. Emphasis is on intuitive understanding of the phenomena, because it reveals the flaws that arise in a purely mathematical analysis.