New SNDR enhancement techniques in pipelined ADC

Signal to Noise and Distortion Ratio (SNDR) is widely chosen for dynamic characterization of ADC. For pipelined ADC in which the inner circuits´ errors accumulate at the output, analysis of the origins of SNDR and its characterization can be very hard. However, due to a relationship between maximum INL of ADC and the distortion in its output codes, SNDR can be derived as a function of maximum INL value and its position in output codes. Utilizing this relationship, this paper develops two methods for SNDR enhancement that do not cost much power. The 50k sampled Monte-Carlo simulation in the behavioral level indicates 75% increase in the possibility of having SNDR > 60db just by utilizing these two methods.