A 2× Blind Oversampling FSE Receiver with Combined Adaptive Equalization and Infinite-Range Timing Recovery

A 2× blind-oversampling, fractionally-spaced equalizer (FSE) receiver is presented as an effective way to combine adaptive equalization and infinite-range timing recovery. A FSE can perform equalization as well as timing adjustment via data-interpolation and the presented work demonstrates an infinite-range timing recovery using a set of two half-UI-spaced, 4-tap FSEs that seamlessly switch across the UI boundaries. A current-integrating summer and multi-input regenerative latch help the 4-tap FSEs and 4-tap DFEs achieve low power dissipation, respectively. A prototype receiver fabricated in a 28nm CMOS consumes 3.5pJ/bit and 0.10mm ² at 9Gb/s while compensating a 22-dB channel loss and a 100 _ppm frequency offset between the transmitted data and blind sampling clocks.