Distribution of return paths for improved impedance control and reduced crosstalk

Abstract

To achieve an even distribution of different types of connections, sets of connection cells have been devised having different ratios of signal, power and ground connections in which the signal connections are all within a maximum distance of a power and/or a ground connection. In addition, the shapes of the cells are such that the cells fit together in a repeatable array that fully covers the plane of the interface, i.e., an array that tiles the plane. Accordingly, to distribute the connections substantially uniformly across the interface, the ratio of the number of signal connections, power connections and ground connections is determined; a cell is selected from the set of cells that has approximately the same ratio of the number of signal connections, power connections and ground connections; and the selected cell is repeatedly used to allocate the signal, power and ground connections in accordance with the distribution of connections in the selected cell until all the connections are distributed.