CUSTOMIZED CROSSTALK NOISE SUPPRESSION PRACTICE IN HIGH-SPEED PCB

A grounded guard trace inserted coupled line layout was proposed to reduce the far-end and near-end noise in the high-speed digital system. A unique methodology was introduced to determine the required no. of grounded vias on the guard trace to minimize the noise coupling. Optimal performance in the time and the frequency domain were obtained for the guard trace with 25 vias configuration. The far-end and the near-end noise voltage are reduced by 54%, 42% compared to the coupled line with 3W spacing. The MEO and MEW values are 0.8V, 0.39nsec respectively. From the scattering parameter results, an average isolation of -35dB for the far-end noise and -45dB for the near-end noise was obtained. The induced far-end and near-end noise voltage is only 0.63%, 0.75% of the signal swing in the active line.