Dynamic element matching using simultaneity tow different techniques for multibit Delta Sigma Modulator

摘要

Mismatch errors in the internal multibit DAC cells in multibit Delta Sigma Modulators (DSM) can limit the Signal to Noise and Distortion Ratio (SNDR) and Spurious Free Dynamic Range (SFDR). The Dynamic Element Matching (DEM) techniques for Digital To Analog Converters (DACs) is an effective approach to achieving good average performance with improving the mismatch shaping in matching critical circuits. This paper present a modified tone free partitioned Data Weighted Averaging (DWA) structure combined with Noise Shaping Dynamic Element Matching (NSDEM) technique to decrease the mismatch noise and remove DAC nonlinearity error. The proposed technique improves both SNDR and SFDR of the DAC. Also by this presented technique becomes more appropriate for low Over Sampling Ratio (OSR) DSM applications which can never obtain by the only one of the used or other methods.