Escape routing of differential pairs considering length matching

The escape routing problem for PCB designs has been extensively studied in literature. Although industrial tools and few studies have worked on the escape routing of differentials pairs, the routing solutions are not good enough by previous methods. In this paper, we propose an escape routing approach of differential pairs considering length matching. The approach includes two stages. The first stage is to find min-cost median points which connect two pins by shortest and equal wire lengths while the second stage is adopted a network-flow approach with min-cost max-flow to simultaneously route all differential pairs. Experimental results show that our approach can efficiently and effectively obtain length-matching differential pairs with significant reduction in maximum and average differential-pair skews.