Last month, TE Connectivity launched one of its thinnest assemblies for speeds of 25 Gbps (and even possibly 50 Gbps) with its new Sliver internal cabled interconnects. Offering a flexible design for making internal input/output (I/O) connections on the board, TE said this new technology simplifies design and helps lower overall costs by eliminating the need for re-timers and costlier, lower-loss printed circuit board (PCB) materials.
According to Nathan Tracy, Technologist, System Architecture Team and Manager of Industry Standards at TE, while the new interconnect was under development, “people exclaimed that it looked as thin as a sliver. The name stuck. This product family is becoming the industry’s next generation solution as a card edge interface that can be used for many tasks.”
Applications include a low-cost, high-density internal cabling solution as required in SAS internal cabling applications; a next-generation, high-performance internal cabling solution for 25 and 50 Gbps applications where PCB loss is unacceptable or where expensive PCBs or additional retimer chips need to be eliminated for lower cost and lower power; and where higher density card edge solutions are needed for next-generation high performance, high-density mezzanines and riser cards.
As rates increase for data communications equipment like servers, switching, routers, and storage, the standard PCB material has too much-uncontrolled signal loss to allow for clean transmission of these signals through PCB traces. TE’s Sliver interconnect product line provides an inexpensive, robust solution with a small, high-density connector and cable assembly that routes high-speed signals from the microprocessors to other locations (e.g. to other boards, to other microprocessor chips, to the backplane, to I/O).
The new design was not without its challenges, because shrinking in size and moving to faster speeds requires careful planning. Tracy added that the new inteconnects support and enable next-generation systems where data rates of 25 Gbps are common and future rates of 50 and 100 Gbps are within sight.
“These next-generation rates were tremendous challenges in developing a connector interface and cable assembly system that delivers excellent return loss and crosstalk performance, all while providing a low-loss link. The connector design and construction needed to carefully balance the conflicting constraints of low cost, high density, and excellent signal integrity,” he said. “Through the use of strong simulation tools as well as applying the experience accumulated on first-generation 25 and 50 G products, our TE development team was able to leverage the right materials and assembly methodologies to yield a robust design that satisfies the conflicting objectives.”
TE’s Sliver products can be used across many applications, data rates, and protocols (including PCI express, SAS, and Ethernet). There are several interconnectivity options, including chip-to-chip, board-to-board, chip-to-front panel I/O, and high-speed card edge. It is a scalable platform that can be extended in increments of eight differential signal pairs for convenient and efficient pin configurations.
Tracy said that emerging challenges faced by higher data rates inspired the new design. “Our customers were being forced to use expensive and power-hungry clock retimer chips within their designs to get the higher rate signals to pass through the long PCB traces they required,” he said. “The high-speed performance of Sliver, combined with the low-loss properties of our twinax cable assemblies, allowed customers to eliminate the retimer chips in some applications and in others, customers are also able to transition to a lower-cost PCB material. Although the project was kicked off to address this need, we saw clear value in also focusing on cost-efficiency, card edge capable receptacle and other configurations, and finally multiple data rates and protocols for maximum versatility and value for customers.”
The new Sliver internal cabled interconnects also solve the design challenge of making products as small as possible with a 0.6-mm contact pitch. This super slim design also has a uniquely robust metal housing on the connector cage to help withstand cable pull, and an active latch on the housing provides additional connection security.
Sliver is offered in a number of configurations to meet a range of design needs. These include both straight and right angle plugs and receptacles, both low-cost and high-performance versions of the cables, and several differential pair contact counts including 16, 24, and 40 pairs.
“Additionally, the family of options will continue to expand as the markets evolves. To achieve the cost-effective design, a modular tooling strategy was chosen to realize the different versions,” Tracy concluded. “The often contradictory goals of a small and high-density solution were a challenge. However, the development team incorporated design features that resulted in a small solution that also delivers on the mechanical integrity in the connector/cable and also in the way it attaches to customers’ equipment.”