Background calibration based on signal-dependent dithering for pipelined SAR ADCs exploiting noise quantiser technique

摘要

A signal-dependent dithering calibration exploiting noise quantiser (NQ) technique to correct capacitor mismatch and inter-stage gain error in pipelined successive approximation register (SAR) ADCs is proposed. With signal-dependent dithering injection, capacitor mismatch and gain error are extracted and subsequently calibrated as one error in the background. Besides, a novel NQ is proposed for a dithering injection only when the residue is near the threshold of the comparator, thereby allowing the injection of dithering without consuming the dynamic range. The simulation results show that the calibration can significantly improve the performance of pipelined SAR ADCs without extra hardware overhead and timing budget.