Review and comparison of RSFQ asynchronous methodologies

The various design limitations imposed on RSFQ circuits through synchronous clocking schemes, make the use of asynchronous clocking attractive. This paper critically reviews and compares a wide range of asynchronous methodologies that have thus far been proposed in the published literature. Circuits are optimized using a Genetic Algorithm optimizer and are then compared in terms of yield, critical margins and latency. A full-adder is also designed and simulated for each methodology to obtain information regarding implementation above the primitive cell level