A Fill-In Technique for Robust IMD Suppression in Chopper Amplifiers Thije Rooije

Abstract

In chopper amplifiers, the interaction between the input signal and the chopper clock can give rise to intermod- ulation distortion (IMD). This chopper-induced IMD is mainly due to amplifier delay, which causes large pulses at the output of the amplifier’s output chopper. This article proposes the use of a so-called fill-in technique to eliminate these pulses, and thus the resulting IMD, by multiplexing the outputs of two identical amplifiers that are chopped in quadrature. A prototype chopper- stabi