Impact on signal integrity of differential pair routing over split plane and voids

Abstract

Differential pair routing on Printed Circuit Board (PCB) level is widely used as interconnection due to its excellent performance in signal integrity. However, differential pair routing is not perfectly immune to the impact of routing discontinuities. This paper analyzes the impact of differential pair microstrip with routing discontinuities by using industrial configuration standard. There are two types of routing discontinuities that are discussed in this paper. They are routing over split plane and routing over void. The results of this research are based on Ansoft HFSS fullwave 3D modeling and analysis simulation. The simulation results consist of three parts which are S-parameter, TDR and full channel transient analysis. The transmission line cross-sectional is based on SATA3 industrial geometry design. From this research, the results show that the impact of differential pair routing with routing discontinuities is significant, in view of signal integrity performance degradation.