An Energy-efficient Multi-bit Quaternary Current-mode Signaling for On-chip Interconnects

We present a multi-bit quaternary current-mode signaling system which transmits two digital signals over one interconnect using current levels and is implemented on a 130nm IBM CMOS process. Measurement results show the multi-bit quaternary current-mode signaling system with data rates of 2.3Gb/s/ch to l.lGB/s/ch and energy of 0.19pJ/b to 0.57pJ/b for wires between 1mm to 5mm respectively. Measurement results also show 2x reduction in energy per bit compared to repeaters for a 5mm wire. Overall, multi-bit quaternary current-mode signaling provides an energy-efficient, crosstalk noise resilient, on-chip interconnect signaling system with data rates comparable to conventional repeaters.