A-DELTA: A 64-bit high speed, compact, hybrid dynamic-CMOS/threshold-logic adder

Abstract

A high speed 64-bit dynamic adder, the Adelaide-Delft Threshold Logic Adder (A-DELTA), is presented. The adder is based on a hybrid carry-lookahead/carry-select scheme using threshold logic and conventional CMOS logic. A-DELTA was designed and simulated in a 0.35 pm process. The worst case critical path latency is 670 ps, which is shown to be on average 30% faster than previously proposed high speed Boolean dynamic logic adders while at the same time reducing the transistor count on average by over 30% compared to the same adders.