Mustafa Yousuf, Hardware Engineer, DEG, Intel
Brahim Bensalem, Senior Hardware Engineer, Intel
Naveid Rahmatullah, Hardware Engineer, Intel

In high-speed design, issues that were previously considered second-order effects, including return path discontinuity and power delivery noise, are now being carefully analyzed. In this paper, we demonstrate how multiple signals that are referenced to a discontinuous plane affect each other. Analysis of a signal that has a return-path discontinuity often doesn’t show a very catastrophic picture. However, when multiple signals are routed over a discontinuous plane, the design fails. We present a methodology to analyze this effect with experimental data to support. This methodology would enable board designers to make the right cost versus signal quality tradeoffs.