This demonstration from DesignCon 2020 shows a 112 Gbps PAM4 connector system which achieves outstanding results.
Ralph Page, System Architect at Samtec, explains that this demo is a collaboration between Samtec and Alphawave. It emulates next generation data center equipment architectures, and incorporates Samtec Flyover® to improve signal integrity and architectural flexibility.
Samtec Flyover routes critical high-speed signals from the ASIC, above lossy PCB materials, directly to the panel, utilizing ultra-low-skew twinax cable.
Signal Path
An Alphawave AlphaCORE-100 MSS SerDes generates two lanes of 31-bit, PRBS data at 112 Gbps PAM4 data rates. Signals travel from the AlphaCORE SerDes test boards, through precision RF cable assemblies, to a Samtec NovaRay™ SI evaluation test board.
The signals then travel through the NovaRay ultra high-density PCB connector and NovaRay cable assembly. Signals then route through 12” of 34 AWG, Samtec Eye Speed® Ultra-Low Skew twinax cable, to a Samtec Flyover Double Density QSFP28 cable system.
The signal path routes through an industry standard QSFP-DD system, to another set of precision RF cable assemblies, and back to the Alphawave test boards, and ultimately back to the AlphaCORE-100 MSS
Results
The Bit Error Rate (BER) is consistently ~3E-9 on both channels. The eye diagrams show the eyes are wide-open, and remember this is PAM4.
The scatter plots and histograms are even, and the slicer output and noise margins are solid.
This demonstration illustrates the advantages of Samtec Flyover. BERs of ~3E-9, pre-FEC, are incredible achievements at these data rates.
Samtec Flyover moves signals off of their traditional pathways — that is, signals are no longer transmitted through copper traces on the PCBs — but they are routed through Samtec Eye Speed twinax cables and high-speed connectors to relay the signals.
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