Optimizing SFQ Circuit Design: A Timing-Driven Framework for Performance-Constrained Area Minimization

Single Flux Quantum (SFQ) digital logic offers a promising path to energy-efficient, high-performance computing, but faces significant scalability challenges–particularly due to the area overhead associated with gate-level path balancing and the pipelining of splitter trees. Prior efforts to reduce this overhead often unnecessarily compromise throughput, diminishing SFQ’s key performance advantage. To mitigate this, we propose a timing-aware optimization framework that unifies and enhances both traditional full path balancing (FPB) and multi-phase clocking approaches. Inspired by timing-driven EDA strategies in CMOS, our approach explicitly models gate delays and jointly optimizes clock phase assignments, pipelining, and splitter tree construction, minimizing area and latency overhead while achieving a given performance target. On benchmark circuits, our timing-aware 2-phase clocking achieves up to 30% area and 29% latency reductions over FPB at a 27ps clock period. Compared to prior multi-phase methods operating at 42ps, we achieve 22% lower area and 23% lower latency. At a tighter 21ps performance target, our timing-aware single-phase clocking improves area and latency by 28% and 7%, respectively. All optimizations are implemented using scalable, polynomial-time algorithms.