Termination of averaging networks in flash ADCs

The averaging technique is used in flash analog-to-digital converters, to reduce the offset voltages resulting from random mismatches in the pre-amplifiers. The averaging network must be properly terminated to avoid systematic deviations on the code transition voltages, at the limits of the input range. This paper reviews the existing terminating strategies and proposes a new one, which makes the averaging network equivalent to the ideal infinite network. HSPICE simulation results are presented to compare all the solutions.