A monotonic digital calibration technique for pipelined data converters

A popular method of digital calibration for pipelined analog-to-digital converters was introduced by Karanicolas et al. (IEEE J. Solid-State Circuits, vol.28, pp.1207-1215, 1993). Although it is tolerant of comparator offset voltages, the algorithm occasionally generates digital correction factors that lead to missing or non-monotonic digital codes. In this paper, the probability of nonmonotonic performance is studied using behavioral simulations, and a calibration algorithm that assures monotonicity in the presence of arbitrary comparator offset voltages and amplifier nonlinearity is introduced.