A 1.41-pJ/b 224-Gb/s PAM4 6-bit ADC-Based SerDes Receiver With Hybrid AFE Capable of Supporting Long Reach Channels
Ahmad Khairi, Yoel Krupnik, Amir Laufer, Yoav Segal, Marco Cusmai, Itamar Levin, Ari Gordon, Yaniv Sabag, Vitali Rahinski, Idan Lotan, Gadi Ori, Noam Familia, Stas Litski, Tali Warshavsky Grafi, Udi Virobnik, Dror Lazar, Yeshayahu Horwitz, Ajay Balankutty, Shiva Kiran, Samuel Palermo, Peng Mike Li, Frank O’Mahony, Ariel Cohen
Abstract
A 224-Gb/s pulse amplitude modulation 4-level (PAM4) ADC-based SerDes receiver (RX) is implemented in a 5-nm FinFET process. The RX consists of a low-noise hybrid analog front-end (AFE) that incorporates both inductive peaking and source degeneration, a 64-way time-interleaved ADC, digital equalization consisting of an up to 30 tap feed-forward equalizer (FFE), optional decision-feedback equalizer (DFE), and a clock-data-recovery (CDR) loop utilizing a 14-GHz digitally controlled oscillator (DCO). The RX was characterized for medium-to-long reach channels (20.6-, 27-, 31.4-, and 38-dB insertion loss at Nyquist) with a corresponding pre-forward error correction (FEC) bit error rates of 1.9E-11, 5.2E-10, 1.2E-8, and 6E-7, respectively. The analog power consumption of the RX is 1.41 pJ/b.