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Authors Saemin Im;Jong-Yoon Shin;Sang-Gyu Park
Page pp.485-491
ISSN 1598-1657
Keywords Delta-sigma ADC; multi-stage noise shaping; SAR ADC; op-amp gain
Abstract Recently, a two-stage MASH type delta-sigma ADC structure, in which a single SAR ADC functions as the quantizer for both the first and the second stages, was proposed. A challenge in the design of the MASH ADC is exact matching between the noise transfer function of the first stage and the transfer function of the digital filters which process the digital outputs. In this work, we show that the mismatch between the filter functions due to the finite gains of op-amps used in the loop filter of the delta-sigma ADC can be greatly reduced by employing correlated double sampling along with the adjustments of the loop gain.