Experimental study of the RSFQ logic elements

Abstract

New elements of the rapid single flux quantum (RSFQ) logic family have been designed, fabricated, and tested. All-Nb 14-layer 5 mu m technology using externally shunted tunnel junctions with j/sub c/=500 A/cm/sup 2/, I/sub c/R/sub s/=300 mu V, and B/sub c/<or=1 has been used. The T-flip-flop circuit has been demonstrated to operate with +or-30% margins at clock frequencies below 50 GHz and with at least +or-10% margins at frequencies up to 120 GHz. Operation of the input (DC/SFQ) and output (SFQ/DC) converters +or-40% margins is also demonstrated.<<ETX>>