Performance of edge tap decision feedback equalization methods for wireline receivers

DFEs are critical building blocks for long-reach wireline receivers, and optimized hardware implementation for low power is key. DFEs use feedback to equalize data samples. This paper evaluates the advantages and disadvantages of applying feedback optimized for the data eye height to the edge samples. Both loop-unrolled and direct feedback taps are considered. A hybrid method is considered where only feedback from direct taps is applied to the edge samples. Examples highlight the cases in which applying DFE to the edge samples either improves or impairs the data eye. These concepts may be used to optimize DFE hardware implementation for minimal power and area.