Analysis and Design of Adaptive Self-Trimming Technique for A/D Converters

A novel self-trimming algorithm for A/D converters [1,2] has been presented which continually trims thresholds in the flash A/D subconverters of two-stage and pipelined A/D converters. Roughly speaking, it trims thresholds up or down by small increments in such a way as to smooth out irregularities in the code density. This paper presents the mathematical analysis and design of the algorithm. The algorithm was analyzed by a novel two-dimensional z-transform introduced in [3], which can be used to demonstrate its stability, predict convergence rate, and which can be used to give a frequency-domain interpretation of the distinct properties of differential and integral nonlinearity.