56 Gbps, PAM4 System
A new breed of cable solution is benefitting designers by reducing board size and improving signal performance — either across the board, between boards, or from board-to-front panel.
The QSFP-DD pluggable form factor, which supports 400 Gbps throughput – that is, 8 X 50 Gbps – is going to define front panel I/O on next generation networking and communication equipment.
Industry leading ICs, like the Xilinx GTM test chip with 56G PAM4 GTM transceivers (shown in this video), combined with products like Samtec’s FQSFP-DD and AcceleRate cable solutions, provide an ideal proof-of-concept for data center communication system architectures.
And besides, Ralph says you’re going to like this demo, so you’re GOING to like this demo and you’d better watch the video. Because you don’t mess around with Ralph, just like You Don’t Mess Around With Jim.
Signal Path and Equipment
The Xilinx GTM test chip is generating one port of 31-5 PRBS data at 56 Gbps PAM4.
The differential pair routes through RF jumpers, to an SI characterization card, to a Samtec cable assembly, and back to a second characterization card.
End 1 of this cable assembly is a Samtec cable AcceleRate system, and end 2 is a Samtec FQSFP-DD interconnect system. In this cable assembly, the data travels through 12” of Samtec ultra-low skew twinax cable.
The signal loops back through more RF jumpers and back to the Xilinx test chip. At the end we see the channel output. The system is running a 5e(-15) Bit Error Rate.
AcceleRate, FQSFP-DD, Flyover
Samtec’s Flyover™ system can help extend signal reach and improve density to achieve next gen speeds, by routing signals via ultra-low skew twinax cable. Flyover is a cost effective, high-performance answer to the challenges of 56 Gbps bandwidth. In another demo you can see how it runs at 112 Gbps.
Samtec’s AcceleRate is a high speed Flyover Cable and High speed mezzanine system in one product family.
The cable assembly has a significantly smaller footprint than any other solution, which is ideal for closer proximity to the IC. It’s high density, up to 92 pairs per square inch.
Samtec’s FQSFP-DD takes the flyover architecture concept to the QSFP-DD form factor.
We’ve already established excellent correlation between this live data and simulation data. So HFSS models area available upon request.
If you want to learn more, please contact our signal integrity team at SIG@samtec.com.
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