A product demonstration that drew a lot of attention at DesignCon 2017 showed how Samtec FQSFP Flyover™ interconnects are used in the Keysight Reference Solution RS506 Digital Interconnect Test System.
The demo has the 32 port Keysight VNA coupled to PLTS measurement software. With this system, one measurement captures all 32 ports. In this video, Jim Nadolny, Samtec’s Principle SI and EMI Engineer, walks us through the demo.
Jim explains how the high-speed signals are routed from a pluggable module, through the FQSFP connector, through low-loss twinax cables, then to a second connector on another board. The switch chip is located on this board. This is called a “Flyover” system, which contrasts with traditional architecture where the high-speed signals come in to a QSFP connector, route into the pcb, and then come up to the switch chip.
Flyover™ uses low-loss twinax cable as a replacement for long reach PCB traces in high performance systems. In short, low-loss, low-skew cables offer SI performance enhancements at high speeds and long distances over the most advanced PCB materials. As Jim explains, in this application, the advantage of Flyover is lower loss, and it enables 56 Gbps PAM4 operation.
Jim references a paper that he presented at DesignCon.
Here’s a link for that paper: Flyover QSFP28 For 56+ Gbps Applications.
The Keysight Technologies Reference Solution RS506 is a Digital Interconnect Test System capable of testing all types of high speed digital backplanes, cables, PCBs and connectors. The Physical Layer Test System (PLTS) N1930B introduced a new software version in 2017 which included major signal integrity analysis features including PAM4 eye diagrams for 100G applications, SCPI commands for automating production testing and Channel Operating Margin (COM) for a single figure of merit for complete channel characterization. More information about PLTS can be found at www.keysight.com/find/plts.
Other Flyover QSFP28 Related Links:
- Here’s the FQSFP28 product overview page
- Flyover QSFP Flyer
- Solving Signal Integrity Problems At Very High Data Rates
- Eric Bogatin’s Three Predictions On The State Of Signal Integrity
- Flyover QSFP Technical Note
- Here’s a link to Jim’s paper
- Here’s a link to Jim’s PPT Presentation