In this video from SC18, Jignesh Shah of Samtec’s High Speed Connectivity Group walks us through a demonstration of a rearchitected Open Compute Project (OCP) wedge switch. By rearchitected we mean it utilizes Samtec Flyover™ high-speed cable assemblies to achieve next gen speeds by routing signals via ultra-low skew twinax cable instead of through the PCB, as in conventional architecture.
The system has a 12.8 Tb Marvell ASIC with 32x QSFP-DD ports on the front panel, sending signals at 56 Gbps PAM4 per channel, through Samtec Flyover cable assemblies. These assemblies, each with 18” of Samtec Ultra Low Skew twinax cable, terminate to Samtec FQSFP-DD connectors on the front panel and to either Samtec NovaRay™ or AcceleRate® connector systems on the ASIC end. The FQSFP-DD connectors accepts a standard, MSA-based QSFP-DD module.
The signal then travels through 3 meters of DAC (direct attach cable) copper cable, then back through 18 inches of twinax cable to the ASIC.
The performance of this system is superior to a conventional architecture. In a conventional architecture, the BER threshold is close 1e-7 for the inner channels and 1e-3 for the outer channels. With this Samtec Flyover system, the BER is as good as 1e-12, Pre-FEC, for all channels. Keep in mind this includes 2x 18” of twinax cable, and three meters of copper direct attach cables.
Here’s a link to another video that details the benefits of using Samtec Flyover technology in these types of applications.
Samtec Connector Products In This Demonstration:
FQSFP-DD: The QSFP-DD form factor focuses on a next generation high-density, high-speed pluggable backwards compatible module form factor. The Samtec FQSFP-DD Flyover product meets this challenge with greater performance margin compared to the QSFP-DD connector-to-PCB approach. As advanced 50+ Gbps per channel ASIC and FPGA solutions hit the market, the next-generation Samtec Flyover approach overcomes the limitations of signal loss on a PCB trace and continues to become more relevant.
QSFP-DD pluggable modules support double the aggregate bandwidth of conventional QSFP modules by adding a second row of contacts which enable support for a 16 differential pair electrical interface (aggregate 200 Gbps NRZ or 400 Gbps PAM4). Systems designed for QSFP-DD modules will be backwards compatible with existing QSFP plug-in modules and provide increased flexibility for end users, network platform designers and integrators.
The Samtec Flyover QSFP system provides improved signal integrity and architectural flexibility by removing critical high-speed signals from lossy PCB materials and transferring directly to the panel via ultra-low skew twinax cable. Double density Samtec Flyover increases throughput over QSFP by adding a second row of contacts enabling support for an eight-lane electrical interface. This is the FQSFP -DD Series.
NovaRay™: Samtec’s NovaRay™ is an industry-leading high bandwidth, high-density interconnect system.
The innovative pin-to-ground differential pair configuration enables very low crosstalk to 40 GHz+, tight impedance control, and minimal variance in data rate as stack heights increase. The system is 112 Gbps PAM4 capable and is rated up to 56 Gbps NRZ per channel. It boasts an industry-leading aggregate average data rate of 1.33 Tbps per square inch. This extreme performance and density is critical as system sizes decrease while speeds increase.
Two highly reliable points of contact contribute to the 112 Gbps PAM4 capabilities, and ensure a more reliable connection, with stub-free mating.
The 92 Ω impedance rating addresses both 85 and 100 Ω applications. An improved breakout region has been developed using a new offset signal-to-ground configuration. NovaRay is initially available in a variety of configurations from 8 to 72 pairs, and can easily be expanded to higher pair counts because of its modular design. Board-to-board configurations include 8 pairs / 448 Gbps aggregate, 16 pairs / 896 Gbps aggregate, and 32 pairs / 1.8 Tbps aggregate. Stack heights range from 7 mm to 20 mm. Right-angle and vertical cable options are in development, which will combine NovaRay with Samtec’s industry-leading Eye Speed® twinax cable. Cable and board interconnects are intermateable.
For more information go to samtec.com/novaray.
AcceleRate®: Samtec’s AcceleRate® cable assembly is the slimmest in the industry with a 7.6 mm body width ideal for closer proximity to the IC. The high-density 2-row design features 8 and 16 pair configurations on a 0.635 mm pitch for up to 92 pairs per square inch.
Rated to 56 Gbps PAM4, this assembly supports Samtec Flyover™ technology via 34 AWG 100 Ω ultra-low skew twinax Eye Speed® cable. This proprietary co-extruded cable supports next-generation performance with extended reach and system flexibility.
Metal latches on both End 1 and End 2 of the cable connectors are standard, as well as standard and reversed wiring options. The mating PCB level connector is the ARF6 series.
For more information go to samtec.com/accelerate.