Signal propagation over perforated reference planes

Voids on reference planes are commonly seen in organic chip packages and printed circuit boards. In this paper, the effects of these voids on the signal integrity of a high-density data bus will be studied. A generic FCPBGA chip package is used to illustrate the signal integrity concerns and perform sensitivity analysis on the key mechanisms including void size, adjacent plane interactions, and adjacent signal line interactions. The results show that proper design can mitigate the signal integrity impact of reference plane voids.