Effect and Sensitivity of Postcursor FFE in a 25 Gb/s High Speed Bus Channel

While equalization is usually a positively contributing factor towards opening eye diagrams further, sometimes over equalization can occur and degrade an eye opening as opposed to improve it. This paper explores the effectiveness of using post-cursors FFE transmitter equalization on 25.78Gb/s communication links with different transmitter and receiver equalization. The effect is observed on two topologies with different loss levels and impedance profiles. Simulation and experimental results are presented and discussed.