A background amplifier offset calibration technique for high-resolution pipelined ADCs

This paper describes a novel offset calibration technique of the residue amplifier (RAMP) for pipelined ADCs. The calibration operates in two phases, completely in the background, without requiring any interruption in the operation of the ADC. In the analog coarse correction phase most of the offset is compensated through the injection of a DC signal at RAMP's input. The digital fine correction phase will eliminate the remaining offset. Simulation results show that with the proposed calibration technique the over-range margin can be released and the SNDR is not degraded.