A 28-nm CMOS 11.2-Gbps Receiver based on Adaptive CTLE and Adaptive 3-Tap DFE With Hysteresis Low-pass Filter

Abstract

This paper proposes a receiver design incorporating both an adaptive continuous-time linear equalizer (CTLE) and an adaptive decision-feedback equalizer (DFE). The CTLE utilizes a merged rectifier and error amplifier, improving the DC gain and reducing the current consumption. Offset cancelation of the CTLE is performed by adaptively adjusting the load resistance of a CTLE cell. The DFE adopts the technique of using a slave latch behind a current summer for the relaxed timing constraint but excludes other auxiliary circuits that perform a master-latch function. The proposed low-pass filter with a hysteresis can suppress the oscillation of the DFE tap coefficients and the data level in the steady state. Fabricated in 28-nm CMOS process, the prototype receiver shows that the measured BER is less than 10<SUP>-14</SUP> at 10.4 Gb/s for an 18-inch FR4 trace and at 11.2 Gb/s for a 12-inch FR4 trace, respectively, with both the adaptive CTLE and the adaptive DFE activated. Operating at 11.2 Gb/s, the energy efficiency of the receiver is 5.36 pJ/bit.