In the field of digital logic, extensive use is made of well known and highly developed complimentary metal-oxide semiconductor (CMOS) technology. As CMOS has begun to approach maturity as a technology, there is an interest in alternatives that may lead to higher performance in terms of speed, power dissipation computational density, interconnect bandwidth, and the like. An alternative to CMOS technology comprises superconductor based single flux quantum circuitry, utilizing superconducting Josephson junctions (JJs), with typical signal power of around 4 nanowatts (nW), at a typical data rate of 20 gigabits per second (Gb/s) or greater, and operating temperatures of around 4 kelvins.
“Fan-in” describes the number of inputs a logic gate can handle. The larger the fan-in, the more inputs can be handled by the gate. Logic gates with higher fan-in can be employed in digital logic design to reduce the depth of a logic circuit, improving circuit efficiency and density. A majority gate is a logical gate that returns true if and only if more than 50% of its inputs are true.