Current-mirror miller compensation: An improved frequency compensation technique for two-stage amplifiers

A novel current-mirror miller compensated two-stage amplifier is presented. The proposed design improves both large-signal performance and small-signal performance of conventional two-stage amplifiers. This design eliminates the low-frequency right half-plane zero and reduces the output parasitic capacitance of the first stage without inducing additional input offset voltage and DC⁸ gain degradation⁸ Detailed ansisi performed to justify the proposed design. The design is simulated in UMC130 CMOS technology. Simulations agree well with analysis. This idea may be extended to multistage amplifiers, low-dropout regulators and other applications.

I. Introduction

Amplifiers are the most widely used building blocks in analog integrated circuits. The system performance is largely dictated by the performances of the amplifiers. Two-stage amplifiers are among the simplest amplifiers and they form the foundation of more sophisticated multistage amplifiers. Classic topologies of two-stage amplifiers were introduced in 1967 [1]. Since then, a lot of efforts have been devoted to study the stability issue of two-stage amplifiers, and many designs with improved performance have been published [2] [3] [4]. A comprehensive summary can be found in [5].