A 16 Gb/s 3.7 mW/Gb/s 8-Tap DFE Receiver and Baud-Rate CDR With 31 kppm Tracking

Abstract

A 16 Gb/s I/O link receiver fabricated in 22 nm CMOS SOI technology is presented. Attenuation and ISI of transmitted NRZ data across PCB channels are equalized with a CTLE feeding an 8-tap DFE. The first tap uses digital speculation and the fol- lowing seven taps are realized by means of the switched-capac- itor technique. Timing recovery and control are performed with a Mueller-Müller type-A baud-rate CDR. The architecture is half- rate and requires one phase rotator. In total, each slice has six comparators to recover data and ti ming information. The second- order digital CDR operates at quarter-rate and features a low-la- tency implementation of the proportional path. At 16 Gb/s, 1 Vppd PRBS31 data transmitted without FFE equalization is recovered across a PCB channel with 34 dB attenuation at 8 GHz. The mea- sured tracking bandwidth is 31 kppm (16 GHz ± 496 MHz), and an amplitude of 3 UIPP is tolerated at 1 MHz sinusoidal jitter. The sinusoidal jitter amplitude t olerance measured at 10 Gb/s is 0.4 UIPP at 10 MHz and remains above 0.2 UIPP up to 1 GHz with PRBS31 data recovered (BER < 10 ) across a PCB channel with 27 dB attenuation at 5 GHz. The power ef ficiency is 3.7 mW/Gb/s, including the full-rate clock receiver.