On dynamic delay and repeater insertion

Abstract

In deep sub-micron technologies, as the wires are placed ever closer and signal rise and fall times go into the sub-nano second region, increased crosstalk has implications on the data throughput and on signal integrity. Depending on the data correlation on the coupled lines, the delay can either decrease or increase. Here we show that in uniform coupled lines, the response for several important switching configurations has a dominant pole characteristic. This allows easy prediction for the average, worst-case and best-case delay of buffered lines. We show that the repeater numbering and sizing can be optimised to deal with crosstalk under different constraints to best match the application. Area and power issues are considered and all equations are checked against a dynamic circuit simulator (SPECTRE).