Dynamic element matching techniques for delta-sigma ADCs with large internal quantizers

Increasing the quantizer resolution in a delta-sigma modulator can increase SNR, improve stability and reduce integrator power consumption. However, each added bit of quantizer resolution causes an exponential decrease in the power dissipation, required area and complexity of the dynamic element matching (DEM) circuit required to attenuate DAC mismatch errors. This paper discusses the prospect of using a segmented feedback path with coarse and fine signals to reduce DEM complexity for modulators with large internal quantizers. Consequences of segmentation are presented, along with two potential solutions: one that uses calibration to cancel mismatch between coarse and fine DACs, and another that frequency-shapes this mismatch error. Analysis and behavioral simulation results are presented.