EMC in Electronic Design

Future electronics applications in the Industrial IoT and harsh environments drive innovation in cable shielding and PCB can miniaturisation.


adio frequency interference (RFI) protection for printed circuit boards and cables is anything but static and is continuing to drive engineers at Portsmouth based Harwin plc to innovate and change the way the company supplies cabling

and other devices to the markets they serve. According to Harwin, these changes are emerging from

industry trends including increased levels of automation in digital manufacturing and more densely populated printed circuit boards (PCBs) arising from both the need for more components on the board and from requirements to reduce the footprint of the board itself. I spoke to Scott Flower, Harwin’s Product Strategy Manager about these trends and the effect they have on cable design and on-board protection.

BESPOKE CABLING According to Flower, users are now demanding whole cable assemblies that are ready-made, protected against RFI and tested. This is a significant change from past requirements when many customers took lower level assemblies. The product set that Harwin offers takes account of the need for compact designs and comprehensive protection against RFI. The company’s 1.25mm pitch Gecko connector is a popular choice for small scale connectivity and Harwin is now able to provide backshells that can be retrofitted to existing cables.

Backshells are machined aluminium alloy components with

electroless nickel plating that provides a Faraday cage for the connector that connects to the cable shielding to provide ground continuity throughout the assembly. They can be used for both cable mount and PCB connectors. The backshell assembly has long been available on the company’s 4-50 way 2mm pitch Datamate cable.

CABLE CONFIGURATION To help companies specify the right cable for the job it needs to do and obtain it ready-assembled and tested, Harwin has now set up a configurator on its web-site, a tool that’s constantly being developed as new options and configurations become available. Part of this comes from the field, where Harwin has a team of Field Application Engineers, who have the role of working with customers on their premises to understand the application and assist in complex configurations, including the consideration of EMC. I asked Flower what challenges the Field Application Engineers were faced with. “Data transmission speeds are

❱ ❱ Scott Flower is

seeing growth in the Industrial IoT and

harsh environment applications

❱ ❱ TOP: Gecko cables now have full shielding including backshells for EMI protection ❱ ❱ PCB clips and removable cans are being made smaller to cope with increasing miniaturisation

becoming higher and the combination of these high data rates and miniaturisation results in the challenges being fed back to our designers, who are considering such factors as material and contact geometry and how these influence the way the signal operates, including taking into account such considerations as cross-talk and EMC,” he tells me. As a result, the product set as well as the configuration tool are in a constant state of development.

BOARD LEVEL PROTECTION Miniaturisation is also affecting board level EMC protection and Harwin has developed a smaller range of clips and cans to cater for this requirement. The clips that are mounted to the board are now much thinner to reduce the gap between the board and the can. “There’s also a corner clip now so the prototyping systems we offer cater for increased densities and board geometries. We’ve achieved a 50% reduction in size whilst still offering the same protection,” says Flower. With increased levels of automation and other harsh

environment applications, Harwin is ensuring its products are robust and so performs vibration testing to its boardware as well as cable connectors to make sure clips and cans don’t displace or lift off the board and change the level of protection.

EMC Testing Vol 2 No. 1 /// 5

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