A low-power high-radix switch fabric based on low-swing signaling and partially-activated input lines

Increasing power density of CMOS ICs and growing complexity of network-on-chips (NoCs) call for energy-efficient, high-radix crossbar switches. This paper demonstrates a design of radix-64 crossbar switch adopting SRAM circuit techniques: low-swing signaling on the bitline and pulse width control on the wordline. By reducing the voltage swing on the high-capacitance wires, both the power and speed can be significantly improved compared to those of a basic matrix-type implementation. The detailed circuit analysis and simulation considering the physical constraints such as wire loading shows that a prototype crossbar switch designed in 45nm CMOS can operate at 2-GHz with 34-FO4 latency and 55.6-fJ/cycle energy efficiency.