Wideband power line isolation using open stub structures

A wideband isolation topology of a power line is proposed, using open stub structures for high-speed digital interconnects. To reduce the coupled noise to the power line in the absence of a common-mode choke (CMC), which could degenerate signal integrity due to its loss and unbalanced properties, ferrite bead and open stub structures are utilised as they are suitable to the small size of commercial systems. In terms of the enhanced isolation characteristics, the induced power noise is reduced from 83 to 12 mV (86% reduction ratio) under a mobile high-definition link data transfer without data losses. Therefore, the proposed open stub structures are a very effective tool for both power integrity and signal integrity, and most importantly the cost is minimal when the CMC is removed from the high-speed digital interconnect.