Correction of operational amplifier gain error in pipelined A/D converters

New techniques for the correction of the inter-stage amplifier gain errors due to the finite gain of the operational amplifiers in pipelined A/D converters are described. The new techniques use a parallel inexpensive (shadow) pipeline to sample, process and accumulate the error. The correction is then performed by adding the processed error signal to the original signal in the analog or digital domain. Behavioral and transistor-level simulation results demonstrate the effectiveness of the proposed techniques in correcting the gain error and improving the accuracy and linearity of pipelined amplifiers and A/D converters