A 10-b 1-GHz 33-mW CMOS ADC

This paper describes a pipelined analog-to-digital converter that resolves 4 b in its first stage and amplifies the residue by a factor of 2, thereby relaxing the opamp linearity, voltage swing, and gain requirements. Calibration in the digital domain removes the effect of capacitor mismatches and corrects for the gain error. Using a one-stage opamp with a gain of 10 and realized in 65-nm CMOS technology, the ADC digitizes a 490-MHz input with a signal-to-(noise+distortion) ratio of 52.4 dB, achieving a figure of merit of 97 fJ/conversion-step.