Rapid single-flux-quantum dual-rail logic for asynchronous circuits

Dual-rail logic circuit elements based on rapid single-flux-quantum (RSFQ) technology have been designed and simulated. The proposed circuits can operate asynchronously, since dual-rail data include timing information in themselves. Therefore dual-rail logic scheme has a possibility of solving some problems of RSFQ circuits with flow clocking, which would become more serious as operating speed and complexity of the circuit increase. Implementation of RSFQ dual-rail AND and XOR cells is described. A scheme of transfer-ring data from a flow-clocked circuit to a parallel dual-rail circuit is also proposed, which a fully asynchronous dual-rail demultiplexer.