Data-Transition Decision Feedback Equalizer with S3-LMS Adaptation Algorithm

This paper presents an adaptive data-transition decision feedback equalizer with a sign-sign-sign least-mean-square (S3-LMS) algorithm. We show in time domain that data-transition DFE performs channel equalization without sacrificing vertical eye-opening when consecutive 1s or 0s are present in data. We further show in frequency domain that data-transition DFE boosts the high-frequency components of data without attenuating their low-frequency components. Moreover, data-transition DFE exhibits a first-order error-shaping characteristic that maximizes vertical eye-opening. A new loop-unrolling scheme specifically tailored for data-transition DFE is presented. The theoretical findings are validated using the simulation results of two 5 Gbps backplane serial links.