Resonator-based multi-stage Sigma Delta modulator for wideband applications with improved dynamic range

Abstract

A new design methodology for wideband, multi-stage, multi-bit YEA modulators (SigmaDeltaMs) with improved dynamic range, is presented. The key to improving dynamic range is to have the first stage oscillated, then the coarse quantisation noise vanishes and hence circuit nonlinearities do not cause a leakage quantisation noise problem. Based on the proposed methodology, a fourth-order four-bit SigmaDeltaM can achieve the dynamic range of 80 dB at the OSR of 8 without using additional calibration techniques.