An active crosstalk reduction technique for parallel high-speed links in low cost wirebond BGA packages

We report a 4-channel 8 Gb/s/channel transmitter test chip assembled in a low cost 4-layer wirebond BGA package to evaluate the impact of active cross-talk mitigation and equalization techniques on signal performance. A half-rate 4-tap feed-forward and a cross-talk induced jitter equalizer is used to compensate package interconnect losses and data dependent signal coupling, respectively. All coefficients of the FFE and crosstalk jitter equalizer have programmable polarity and magnitude. The chip power dissipation is 225 mW, or 7 mW/Gb/s. The FFE and jitter equalizer achieves a measured RMS jitter reduction of 7.5-ps for an improvement of 50%.