Design-oriented analysis for miller compensation and its application to multistage amplifier design

Abstract

A design-oriented analysis (DOA) method is presented which lends sufficient insights into various Miller compensation schemes. The method predicts the nondominant poles of the Miller compensated amplifiers in an intuitive manner and it serves as a good supplement to the conventional analysis. The usage of DOA is verified by the various design examples given in the manuscript. Guided by DOA, two kinds of frequency compensation schemes are proposed for Miller compensated multistage amplifiers capable of driving a large capacitive load (CL) with low power consumptions. Both schemes employ an active zero to extend the bandwidth of their Miller feedback loops, thereby pushing the amplifier’s nondominant poles to high frequencies and achieving larg gain-bandwidth (GBW). Both prototypes are designed and fabricated in a in a 0.18-$mu$m CMOS process. The measured results show improved figures-of-merit (FOM) compared with prior state-of-the art Miller compensated multistage amplifiers.