Design of Complex Rapid Single-Flux-Quantum Cells with Application to Logic Synthesis

This paper presents designs of rapid single flux quantum (RSFQ) logic cells comprising multiple (more than two) inputs and high-fanout splitters, which are subsequently utilized by an automated logic synthesis flow to reduce the area/power costs and logic depth of RSFQ logic circuits. The complex cells include multi-input AND and OR gates as well as specialized gates such as A+BC. The logic synthesis tool builds on the ABC tool, but adds features and capabilities that are unique to RSFQ circuits. Results show a sizeable reduction in the Area-Delay product of large multiplexer, decoder, and carrylook- ahead adder circuits while exhibiting small (manageable) degradation in margins.