Logic operation at 5 gb/s of an output interface for single-flux-quantum systems

High-speed logic operation of an output interface circuit for a single-flux-quantum (SFQ) system was demonstrated at a data rate of 5 Gb/s. Using NEC's 2.5-kA/cm/sup 2/ Nb junction process, we designed, fabricated, and tested the interface circuit consisting of a 2-b SFQ demultiplexer and two Josephson latching drivers. We verified the proper operation of the demultiplexer. The interface can convert 5-Gb/s SFQ-pulse data into two-channel 2.5-Gb/s return-to-zero data with an amplitude of approximately 6 mV.