Lubricated Tin-Nickel for High-Speed Connector Ground Contacts: A Reliable Interface

In a previous paper, the authors reported results of product-level electromagnetic simulations performed to assess the impact of elevated DC contact resistance, at the ground contact interfaces, on the signal integrity (SI) performance of a high-speed connector. The results indicated that the SI performance is not affected significantly by stable ground DC contact resistances, even in the ohmic range. Further, these results agreed with the fundamental literature. The paper also compared the laboratory-scale performance of a lubricated tin-nickel alloy with that of a gold-based connector finish, typically used on ground contacts of high-speed products. Connector-level accelerated tests newly reported here, conducted according to industry standards, demonstrate that expensive gold-based connector finishes can be replaced by the identified tin-nickel-based finish in high-speed grounds without significantly affecting the SI performance over the operational frequency range of the product. Additionally, a rigorous analysis of the connector-level data indicates that the low-cost finish offers reliable performance correlating to field life of greater than 20 years at only a fraction of the metals cost associated with typical gold-based finishes.