A $2\times 50\ \text{Gb}/\mathrm{s}$ Single-Ended MIMO PAM-4 Crosstalk Cancellation and Signal Reutilization Receiver in 28 nm CMOS

This paper presents a dual-coupled single-ended (SE) receiver with crosstalk cancellation and signal reutilization (XTCR) technique in 28 nm CMOS process. The asymmetric-inductor SE to differential converter (S2D) is proposed to eliminate the mismatch at its pseudo-differential outputs. The conventional and the proposed active crosstalk extraction (AXTE) techniques are adopted to one of the two SE lanes, respectively. Compared to the conventional one, the proposed AXTE technique can compensate for higher insertion loss without extra power consumption, and improve the measured horizontal and vertical eye openings by 17% and 18% at 28 Gb/s NRZ, respectively. Moreover, the PAM-4 XTCR scheme is realized for the first time, and the measurement results show that it achieves an efficiency of 0.85 pJ/bit/lane for
$2\times 50\ \text{Gb}/\mathrm{s}$
with a pair of 10-inch PCB traces.