Innovative 28 Gb/s Quarter Rate Receiver with Data-rate-tolerant Adaptive Continuous-time Linear Equalizer

Abstract This paper presents a 28 Gb/s receiver with a data-rate-tolerant adaptive continuous-time linear equalizer (CTLE). The adaptive CTLE works based on the spectrum balancing method. An equalizer boost control loop is used to adjust the equalizer boost while a corner frequency control loop guarantees data-rate adaption. The speed of similar devices is limited by the necessary slicer. In this study, rather than the output signal of a slicer, the recovered data is used as the input for the corner frequency control loop. A data sampler may have oversize bandwidth during the sample period and a high gain during the regeneration period, thus the proposed structure can secure a clean waveform at high speeds. The quarter rate structure further relaxes the slicer-related speed limit. The receiver consumes 232.2 mW with a 1.2V supply when realized in 55-nm CMOS technology while the equalizer consumes 70 mW.