Flyover QSFP28 For 56+ Gbps Applications

At DesignCon 2017, Jim Nadolny, Samtec’s Principle SI and EMI Engineer, presented⁽¹⁾ a technical paper entitled “Design of Flyover QSFP28 (FQSFP Series) for 56+ Gbps Applications.”

This white paper discusses the Flyover QSFP (FQSFP) approach for 56+ Gbps applications to overcome the limitations from the large loss on typical QSFP ports with surface mount to PCB traces. By replacing the PCB traces to twinax cables, they achieved 7 dB lower insertion loss at 40 GHz — compared to that of PCB trace with a low loss substrate — for the 12-inch path from the switch IC to the connector.

To investigate the EMI aspect of the FQSFP approach, they developed a simulation model of the FQSFP. The model showed a good correlation with measured TDR at the FQSFP port and TRP (total radiated power) from the FQSFP in a test vehicle. TRP from the FQSFP without a shielding cage is -8 dBW, and -12 dBW at 15 GHz from 1 W input power for common-mode and differential-mode, respectively.

Related Links:

• Here’s a link to the paper
• Here’s a link to the PPT Presentation
• Here’s the 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

Other products featured at DesignCon include:

ExaMAX^® high-speed backplane system (EBTM/EBTF-RA Series) enables 28 Gbps performance on a 2.00 mm column pitch with a roadmap to 56 Gbps. This rugged system has the industry’s lowest mating force with excellent normal force, a 2.4 mm contact wipe and two points of contact for high reliability. Among other industry specifications, ExaMAX^® exceeds OIF CEI-28G-LR for 28 Gbps standards and meets the Telcordia GR-1217 CORE specification. The roadmap for ExaMAX^® products includes cable, direct mate orthogonal, mid-plane orthogonal and coplanar.

Edge Rate^® HD – Samtec’s new 0.635 mm pitch, high-speed, multi-row strip – packages the same reliable contact system and ease of processing found in the SEARAY^™ family in an even smaller and higher-density strip design. With both the four-row (5 mm wide) and two-row (2.5 mm wide; in development) versions capable of supporting 28+ Gbps applications, as well as multiple next-generation protocols, Edge Rate^® HD (EDM6/EDF6 Series) is the future of high-speed strips at Samtec, and in the industry.

Samtec’s x4 duplex 28 Gbps FireFly^™ optical engine (ECUO Series) brings its industry-leading density to the 100 Gbps Datacom/Telecom and HPC markets. Designed with thermal optimization in mind, options are available for both forced air and cold plate cooling scenarios. The integral dual-band CDR was designed to work with the latest Ethernet and InfiniBand^™ protocol specifications. This x4 duplex architecture, while offering an extremely small footprint on the board, makes FireFly^™ ideal for communications within a rack, or between racks.

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⁽¹⁾ Jim was the presenter at DesignCon, but the paper was authored by:

• Kyoungchoul Koo, Missouri University of Science and Technology.
  • [kckoo84@gmail.com]
• Pranay Vuppunutala, Missouri University of Science and Technology.
  • [pv6zf@mst.edu]
• Atieh Talebzadehghahroudi, Missouri University of Science and Technology.
  • [ath27@mst.edu]
• Jim Nadolny, Samtec, Inc.
  • [jim.nadolny@samtec.com]
• Yuan Chen, Missouri University of Science and Technology.
  • [ycwnd@mst.edu]
• Qian Wang, Xilinx Inc.
  • [qian.wang@xilinx.com]
• James L. Drewniak, Missouri University of Science and Technology.
  • [drewniak@mst.edu]