A multi-pole single-tap IIR based DFE equalizer topology

Decision feedback equalizer (DFE) using finite impulse response (FIR) feedback filter forms the backbone of modern wireline communication receivers. Incorporating infinite impulse response (IIR) feedback filtering in DFE is an upcoming area of research owing to the inherent power efficiency of analog filtering. Till date, multiple pole IIR based DFEs have been primarily implemented using multiple, single-pole IIR filters. In this paper, we propose a new architecture that can replace multiple single-pole IIR filters with a single IIR which has multiple poles, thus saving area and power compared to its predecessors. The proposed architecture can be tuned for existing wireline channels whose pulse-responses are characterized by long tails. Simulations of the proposed architecture in 65-nm UMC65-SP show more than 50% improvement in eye height and more than 25% improvement in timing jitter for cascaded B12 and cascaded T12 channels at 8-Gbps.