A self-adaptive digital calibration technique for multi-channel high resolution capacitive SAR ADCs
This paper introduces a self-adaptive digital technique to calibrate multi-channel SAR ADCs. Rather than achieving higher resolution by adjusting the analog component values, this new digital method infers the capacitor weights of a SAR ADC with the help of a channel-shared high resolution sigma-delta ADC, which results in remarkable improvements in the capacitive SAR ADCs' property. ENOB increases from 11.06 bits to 12.67 bits. The digital calibration logic is based on LMS (least mean squares) and gradient descent.