A 20‐Gb/s 4‐tap time‐domain DFE with pulse width modulation for a DQ‐DQS matched parallel receiver

A 4‐tap time‐domain decision feedback equalizer (TD‐DFE) is presented to implement a multi‐tap DFE in a matched DQ (data)‐DQS (strobe) tree architecture. Traditionally, matched architecture holds an advantage in terms of power noise immunity, but it suffers from low‐speed performance due to the unavailability of decision feedback equalizer (DFE) applications. By adopting the proposed TD‐DFE, both high‐speed operation and power noise immunity can be achieved within the matched architecture. An 8‐DQ parallel receiver with the proposed 4‐tap TD‐DFE, designed in 28 nm CMOS, achieves a data rate of 20 Gb/s with 0.6 UI eye‐opening even with 215 mV power fluctuations.