Twisted-Overlap Differential-Pair Approach to Increase Available Layout Space and Reliability in PCB Design

Modern electronic products require many high-speed differential pairs which require more layout space in PCB design. We propose a twisted-overlap differential-pair (TODP) structure to obtain more routing space and achieve better signal integrity in this study. TODP reduces the layout space requirement by about 25% compared with that required by traditional differential pairs and the twisted differential lines (TDL) structure [2]. Based on an eye diagram performance the TODP design compared to the traditional and TDL designs can improve the peak-to-peak jitter by 26.5% and 12.2%, the overshoot by 14.3% and 2%, the undershoot by 18.8% and 5%, and the eye width by 2 and 1%, respectively. Our results indicate that TODP may be of great benefit in differential-pair PCB design.