1. [Publications](/publications) 2. A 0.297-pJ/Bit 50.4-Gb/s/Wire Inverter-Based Short-Reach Simultaneous Bi-Directional Transceiver for Die-to-Die Interface in 5-nm CMOS # A 0.297-pJ/Bit 50.4-Gb/s/Wire Inverter-Based Short-Reach Simultaneous Bi-Directional Transceiver for Die-to-Die Interface in 5-nm CMOS ![](/sites/default/files/styles/wide/public/publications/ISR_JSSC_0.jpg?itok=YkdYVZcN) This article presents a clock-forwarded, inverter-based short-reach simultaneous bi-directional (ISR-SBD) physical layer (PHY) targeted for die-to-die communication over silicon interposers or similar high-density interconnect. Short-reach links of this type are increasingly important to support larger systems built with chiplets and multiple die and to facilitate the shift to medium- and long-range optical communication based on silicon photonics. This project explores the advantages of simultaneous bi-directional signaling (SBD) over other bandwidth-doubling techniques (e.g., PAM4). Fabricated in a 5-nm standard CMOS process, the ISR-SBD PHY demonstrates 50.4 Gb/s/wire (25.2 Gb/s each direction) and 0.297 pJ/bit on a 750-mV supply over a 1.2-mm on- chip channel. ## Authors [Yoshinori Nishi](/person/yoshi-nishi) John W. Poulton (NVIDIA) [Walker Turner](/person/walker-turner) [Xi Chen](/person/xi-chen) [Sanquan Song](/person/sanquan-song) [Brian Zimmer](/person/brian-zimmer) [Stephen Tell](/person/stephen-tell) [Nikola Nedovic](/person/nikola-nedovic) [John Wilson](/person/john-wilson) [William Dally](/person/william-dally) [Tom Gray](/person/tom-gray) ## Publication Date Saturday, April 1, 2023 ## Published in [IEEE Journal of Solid-State Circuits ( Volume: 58, Issue: 4, April 2023)](https://ieeexplore.ieee.org/document/10011563) ## Research Area [Circuits and VLSI Design](/research-area/circuits) ## Copyright This material is posted here with permission of the IEEE. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to .