Interconnection


Flyover cables vs PCB tracks

30 August 2023 Interconnection

Samtec’s Flyover cable systems are designed to get signals off the PCB to improve signal integrity, increase design flexibility, and optimise thermal performance. These products route high-speed signals through low-loss, low-skew twinax cable. They operate across distances that can be up to several metres long, while removing the need for clock data recovery circuits (CDRs) or re-timers.


Figure 1. Samtec Flyover cable system.

In a recently published white paper, Samtec Senior Field Applications Engineer, Anthony Fellbaum, provides measured data and examples to explain why a cable solution can be better in a high-speed design than a PCB trace. It also addresses concerns such as cable management and cost.

In the published analysis, Samtec’s Flyover cable demonstrated significantly lower loss than and PCB grade material. Figure 1 shows a comparison of the magnitude (in dB) of insertion loss for three typical PCB materials and two gauges (30 and 34 AWG) of Samtec Flyover cable. For easier scaling and comparison, a 10-inch length of cable was used.

The figure shows that for a high-speed signal running at 14 GHz, the traditional PCB material (shown in yellow) is very lossy. As can be seen, even the best PCB performance is well below the Samtec low-skew high-speed twinax cable (30 AWG shown in green, 34 AWG shown in blue).

Specifically, a 30 AWG cable demonstrated an insertion loss of 1,21 dB for 56 Gbps PAM4, or -1,8 dB for 112 Gbps PAM4. The 34 AWG cable exhibited an insertion loss of -1,9 or -2,9 dB for the same data throughput.

Also shown in figure 1 is the affect that temperature has on the stability of the signals. PCB materials have a significant drop in performance over temperature. By comparison, the twinax cable has a very stable performance, which is thanks to the low moisture absorption properties of the dielectric used in the cable.

The full white paper can be freely accessed in the Samtec technical library: www.samtec.com/support/tech-library


Credit(s)



Share this article:
Share via emailShare via LinkedInPrint this page

Further reading:

What’s the big deal with open pin fields?
Spectrum Concepts Interconnection
The concept behind the open pin field array is that it provides many contacts that are not limited to a single role.

Read more...
Hirose Electric’s push-on bayonet lock connectors
Avnet Abacus Interconnection
Hirose Electric’s HR22K Series is a compact, waterproof, and oil-resistant connector designed for demanding industrial environments.

Read more...
Halo mid-board optical transceiver
Spectrum Concepts Opto-Electronics
The Samtec Halo mid-board transceiver has been designed for next-generation embedded applications that require 56 and 112 Gbps PAM4 performance in low profile and ruggedised form factors.

Read more...
Innovation in high-frequency cable design
Spectrum Concepts Telecoms, Datacoms, Wireless, IoT
[Sponsored] With frequencies approaching 110 GHz, a mismatch in impedance, an increase in insertion loss, or minute phase distortion can be the difference between success and failure.

Read more...
New connector for Push-X technology
Phoenix Contact Interconnection
Phoenix Contact is extending the series of PCB connectors with innovative Push-X technology to include a new connector for conductor cross-sections up to 2,5 mm2.

Read more...
Test cable designed for maximum ruggedness
Conical Technologies Interconnection
The Anoison PT test cable is designed for maximum ruggedness using a high-quality raw cable, connector, and smart armouring module.

Read more...
Safe connection under load
Phoenix Contact Interconnection
The ArcZero DC connectors from Phoenix Contact can be safely connected and disconnected under load, providing operators with reliable protection against hazardous electric arcs.

Read more...
Time-To-Market interconnect solutions
Interconnection
TTM Technologies are at the forefront of electrified powertrains, vehicle charging stations, and energy storage solutions, providing thermal management, high-current capabilities, and specialised solutions.

Read more...
Connectors for energy storage systems
Phoenix Contact Interconnection
The new Phoenix Contact BPC series connectors are protected against polarity reversal making them ideally suited for use in energy storage systems.

Read more...
What’s the big deal with open pin fields?
Interconnection
The concept behind the open pin field array is that it provides many contacts that are not limited to a single role.

Read more...