Clockless Dynamic SFQ and Gate With High Input Skew Tolerance

We have introduced a new class of dc-powered Single Flux Quantum (SFQ) logic that uses dynamic (self-resetting) internal states to achieve completely clock-free gate operation and provide high immunity to input data skew. We call it DSFQ (dynamic SFQ) logic. We have successfully designed and tested a 2-input DSFQ and gate and showed its ability to hold dynamically its internal states for over 25 ps while operating at 10 GHz clock frequency. We also demonstrated picosecond-scale dynamics of DSFQ circuit with an on-chip Josephson sampler, with only low-speed interfaces required.