PCB only solution for 112Gbps VSR channels for ethernet switches

Ethernet speeds of 112Gbps/lane pose significant challenges for designing switch systems to meet increased throughput demands of today’s data centers with high traffic volumes from artificial intelligence (AI) servers. Due to increased PCB losses at such high frequencies, fly-over cables are being promoted for the longest length channels. Fly-over cables pose manufacturing reliability and mechanical challenges for the system design; along with increased system cost. System designers prefer to have PCB only solution. Development in PCB materials and current data rates have brought us to a stage where copper losses dominate than the dielectric losses. In this scenario, copper-roughness modeling becomes even more important than before. When it comes to Cu-roughness modeling, there are a lot of parameters that are used in datasheets. Furthermore, there are a lot of Cu-roughness models available in literature compounding the issues system designers have to take into account. It is important to identify operating regime of the design parameters and adopt an approach that results in practical outcomes. This study captures state-of-the-art developments in materials, processes and modeling methodologies to meet today’s design challenges. This work shares our design approach to the upcoming switch systems to meet high throughput demands.