In this new video, Samtec’s Kevin Burt introduces Samtec Direct Connect™. Direct Connect gives the benefit of exiting a higher number of lanes at low loss from the chip package, which can be very useful in both high performance computing and network switching applications, especially at 56G/112G PAM4.
Samtec is the only company that offers both optical and copper connectivity to the same connector, giving designers the flexibility of choosing the appropriate solution for their application.
Most Samtec Flyover® architectures are mid-board applications, meaning the signal launches from the cable assembly located next to the chip. Others are front panel pluggable.
With Direct Connect, the cable interface is on the package where the high speed signals connect directly to the silicon package. The signal path is from the die, to a Samtec UEC5 connector, to the FireFly® optical engine.
Kevin explains that the demo has eight BGA-style packages, all with Direct Connect technology. Three of them are Direct Connect with Samtec Flyover to QSFP-DD. These incorporate Samtec 34 AWG Eye Speed® ultra-low skew twinax cable. The system in the video has 32 Direct Connect assemblies, routing to 16 QSFP-DD ports.
One connects directly to a backplane, also using Samtec 34 AWG Eye Speed ultra-low skew twinax cable. While connecting directly to the chip, we could also directly connect to the front panel ports using the same Samtec Flyover technology.
The other four BGAs are Direct Connect with Samtec Flyover optical FireFly assemblies. These terminate to 16, MTP x 24.
Overview Of Results
We took one of the optical channels and connected it to a Keysight scope. The wide opening of the 56 Gbps PAM4 optical eye pattern shows plenty of margin for the designer to use for the next generation system.
The demonstration shows the architecture of how you could design a 12.8 Tb system in a 1 RU chassis, with this example having five cooling fans, a backplane connector and space for two power supplies.
Benefits Of Direct Connect
With this technology, high speed signals connect directly to the silicon package which eliminates distortion through the BGA region. Direct Connect also improves power efficiency. The optical solution enables 56 Gbps PAM4 at a pJ/bit that is three times more efficient than QSFP25.
And, of course there are density advantages. FireFly technology allows designers to launch many more high speed signals than is available with conventional technology as we are not just limited to the BGA density. Also, the optical system provides up to twice the front panel density of QSFP-DD.
The interconnect is removeable and interchangeable with both active optics and high-speed Flyover Twinax cable assemblies. Thermal analysis demonstrate that this solution is feasible for both air-cooled and cold plate-cooled systems.