(An) adaptive decision feedback equalizer based on eye-opening monitor to compensate far-end crosstalk

Abstract

In High Bandwidth Memory (HBM) systems utilizing a large number of I/Os, increasing the number of transmitting I/Os can enhance the overall data transfer rate. To increase the I/O count within the same PHY area, the channel spacing in the silicon interposer connecting the HBM and the processor needs to be reduced. However, a denser interposer spacing exacerbates crosstalk, a form of interference between transmission channel data, and, along with the channel's inherent insertion loss, significantly diminishes signal integrity. Therefore, this study proposes a circuit to effectively compensate for both crosstalk and insertion loss. It leverages the data pattern dependency of the transmission channel's post-cursor and crosstalk to statistically adapt and determine the optimal sampling points for each adjacent channel and the target transmission channel. Subsequently, a decision feedback equalizer is employed to apply the appropriate sampling points for each pattern, thereby compensating for crosstalk and insertion loss.