Effects of mounting pads and length imbalance on performance of fast differential interconnects

High-speed interconnections (links) on printed-circuit boards (PCBs) are usually implemented as differential communication links capable of transferring data at multi-gigabit-per-second rates. However, to achieve these communication speeds, many issues must be carefully addressed. This paper investigates effects of connecting an AC coupling capacitor in series with the PCB trace and effects of unbalance in lengths of differential traces on the link performance.