Analysis and Design of Operational Amplifier Stability Based on Routh-Hurwitz Stability Criterion

Abstract

This paper proposes to use Routh-Hurwitz stability criterion for analysis and design of the opamp stability, when its small equivalent circuit is derived; this can lead to explicit stability condition derivation for opamp circuit parameters. In the theoretical part, we describe the equivalence between Nyquist and Routh-Hurwitz stability criteria under some conditions, and we deduce the relationship that between parameters of Routh-Hurwitz stability criterion and phase margin of the operational amplifier. In the verification part, our statement is confirmed with LTspice simulations at transistor level opamp circuits.