32Gb/s data-interpolator receiver with 2-tap DFE in 28nm CMOS

In next-generation communication standards, such as OIF CEI-28G-SR and CEI-56G-VSR, the data rate has to be doubled or quadrupled compared to the current standards. Though transceivers for a data rate over 25Gb/s have been reported [1-3], designing clock-generating circuits for the receiver front-end is a significant challenge. In a phase interpolator (PI) commonly used in conventional receivers for a multi-channel configuration, both the linearity and frequency characteristics of the circuit affect the interpolation accuracy since it dynamically interpolates between reference clock signals supplied from a PLL, making the design more difficult. Blind-clock ADC-based receivers [4] eliminate the need for a clock-phase-adjusting circuit, but the area and power overheads are large due to high-sampling-rate ADCs. To address these issues, we fabricate and test a 28nm CMOS blind-clock receiver that performs phase tracking by using a data interpolator (DI). We confirm error-free operation of the receiver up to 32Gb/s with power consumption of 308.4mW from a 0.9V power supply.