You are about to enter the World of RSFQ -- one of the most
exciting, most unusual and most promising superconductor
technologies of the Tomorrow. RSFQ stands for Rapid
Single-Flux-Quantum Logic/Memory Family.
Typical speed of RSFQ devices fabricated using an
obsolete 3.5um technology is close to 100GHz (20GHz
clock). The ultimate speed of an RSFQ device ever measured
experimentally is 770GHz.
In RSFQ, information is stored in superconductor loops as
tiny magnetic flux quanta and transferred as several
picosecond-wide voltage spikes with quantized area. The tiny
and quantized nature of magnetic flux quanta significantly
(by several orders of magnitude) reduces crosstalk and power
consumption, as compared to CMOS devices.
There are no combinational RSFQ gates in the
traditional understanding of this word. Most of RSFQ
elementary cells combine logic functions and storage
capacities, acting as "smart" flip-flops and giving
designers a plenty of unique opportunities.
There are almost 30 elementary cells available for an RSFQ
digital designer. Among them: transmission lines, splitters,
mergers, memory cells, flip-flops, inverters, logical cells
(AND, OR, XOR), converters...