2.7 A coefficient-error-robust FFE TX with 230% eye-variation improvement without calibration in 65nm CMOS technology

This paper presents a 4-tap coefficient-error-robust feed-forward equalization (FFE) transmitter (TX) for massively parallel links. Recently, massively parallel links such as on-chip links [1-3], silicon interposers [4,5], or wide I/Os [6] are gaining popularity to meet increasing demand for data transmission with a limited power budget. However, calibration overhead for thousands I/Os to compensate coefficient errors due to nano-scale variation has a high hardware cost. To reduce this overhead, we develop a coefficient-error-robust FFE (B-FFE) TX architecture that uses the channel loss to suppress eye perturbation due to coefficient errors while behaving identically to a conventional FFE.