A mutual characterization based SAR ADC self-testing technique

Abstract

This paper presents a self-testing technique for split-capacitor-array SAR ADC. In the proposed mutual characterization methodology, the capacitor array is reconfigured so that one sub-array assists the bit weight extraction of the other. Taking advantage of the split-capacitor-array architecture, mutual characterization incurs much less area overhead than previous works. From obtained bit weights, the capacitor mismatch induced nonlinearity can be derived and further calibrated via external digital calibration. Simulation results show that the proposed technique achieves high DNL/INL estimation accuracy and substantially improves the SAR ADC linearity.