4-Gb/s Parallel Receivers With Adaptive FEXT Cancellation by Pulse Width and Amplitude Calibrations

Two 4-Gb/s parallel receivers with adaptive far-end crosstalk (FEXT) cancellation are presented, which requires a calibration mode. A digitally controlled high-pass filter and a variable-gain amplifier are used to generate the crosstalk cancellation (XTC) signal. The pulse width and amplitude of the XTC signal are automatically calibrated to match the FEXT signal for different channel spacing. It is expected to minimize the residual FEXT signal. Two receivers using the proposed adaptive XTC are fabricated in 40-nm CMOS technology and the core area occupies 0.045 mm². The power consumption from a 0.9-V supply is 19.8 mW. For two 4-Gb/s PRBS of 2⁷ - 1 passing through FR4 PCB traces with 5-in long and 8-mil spacing, the measured peak-to-peak jitter of data is reduced by 27.78 ps by using the proposed adaptive XTC.