Digital calibration of capacitor mismatch and comparison offset in Split-CDAC SAR ADCs with redundancy

This work introduces a digital technique to measure and correct the mismatch between capacitors in SAR ADCs with split capacitor-based DAC (CDAC), including the bridge capacitor impairments. The method takes advantage of redundancy for calibration with negligible impact on the analog section. It reuses some of the capacitors in the array to also compensate the comparison offset, preventing redundancy interval saturation during the error measurement phase. The effectiveness of the method is demonstrated by realistic behavioral simulations in a 12-bit split-CDAC SAR ADC case study.