Digital calibration of inter-stage nonlinear errors in pipelined SAR ADCs

Abstract

Two digital calibration techniques to linearize the residue amplifier in pipelined SAR ADCs are presented. The proposed techniques utilize a single, one-bit pseudorandom noise (PN) to simultaneously identify all coefficients of a correction polynomial. Behavioral simulation results demonstrate the effectiveness of the two proposed techniques, in which the SNDR and SFDR of a 12-bit pipelined SAR ADC are improved from 54 and 69 dB to 72 and 100 dB, respectively. Some circuit design details are included for the PN injection circuit as well as the digital calibration logic.