Pulse-driven delay-insensitive circuits using single-flux-quantum devices

Recent progress in device technology is disclosing a fundamental limitation in synchronous system design. A natural solution to this problem is the introduction of asynchronous or event-driven computing. Delay-insensitive circuits are a class of asynchronous circuits that operate correctly even in the presence of unbounded gate and wire delays. An interesting application of the delay-insensitive design discipline is the use of the rapid single-flux-quantum (RSFQ) devices which is one of the superconductive Josephson-junction devices. This paper introduces a pulse-driven delay-insensitive logic using RSFQ devices and proposes a set of primitive element models which has been validated by an analog simulation. The paper also discusses several challenges toward dependable and ultra-high performance computing with the pulse-driven logic