2nd-Order shaping technique of the DAC mismatch error in noise shaping SAR ADCs

摘要

A switching scheme to realize 2nd-order digital-to-analog converter (DAC) mismatch error shaping (MES) technique in the high-resolution noise shaping successive approximation register analogue-to-digital converters (NS SAR ADCs) is proposed. By feeding back the combination of the least significant bit (LSB) DAC mismatch errors in two previous cycles, the DAC mismatch error is 2nd-order shaped. The scheme only requires an extra reference voltage and triples LSB DAC, which leads to simple control logic. According to the simulation, the spurious-free dynamic range is improved 10 dB more than the 1st-order MES.