A 0.3 pJ/bit 20 Gb/s/Wire Parallel Interface for Die-to-Die Communication

A high-density low-power parallel I/O for die-to-die communication is presented. The proposed interface includes a low-power transceiver and a high-density low-cost silicon interposer. The link architecture exploits single-sided and capacitive termination, passive equalization in the transmitter, and CMOS logic-style circuits to reduce the power consumption. To achieve a high bump/wire efficiency, single-ended signaling is used. A 4-layer Aluminum silicon interposer is fabricated providing 2.5 mm and 3.5 mm links between prototype transceivers. The transceiver prototype includes 3 transmitters and 3 receivers fabricated in 28 nm STM FD-SOI CMOS technology. The parallel interface operates at 20 Gb/s/wire and 18 Gb/s/wire data rates over the 2.5 mm and 3.5 mm channels with 5.9 and 7.7 dB of loss relative to DC (10.7 and 13.5 dB total loss) at fbit /2 while consuming 0.30 and 0.32 pJ/bit excluding clocking circuits, respectively.