Low noise chopper instrumentation amplifier with feed-forward ripple suppression technique

Abstract

A low noise chopper instrumentation amplifier (IA) with proposed feed-forward ripple suppression (FFRS) technique is presented in this paper. Employing a feed-forward path followed by a ripple suppression transfer function, the proposed technique eliminates the output chopping ripples significantly. In addition, ripple suppression is achieved without much current consumption overhead. The chopper IA is designed for high input impedance along with minimized noise floor essential for signal conditioning circuits of biopotential signals. Simulation results, using UMC 65 nm CMOS technology, reveals that the proposed FFRS technique achieves an input referred ripple equals to 0.28 μV corresponding to 68 dB of ripple suppression. Moreover, the DC input impedance of the chopper IA is 6 GΩ. The overall chopper IA achieves an input noise power spectral density (PSD) equals to 55 nV/√Hz and bandwidth equals to 1 kHz with supply voltage equals to 1.2 V.