New-Tech Europe Magazine | Jan 2018

more resilient towards shocks or vibrations. To achieve multiple plugging and releasing, the contact members have to adapt to each other without plastic deformation (Picture 1c) Adjustable flex arms which deform elastically are the basis principle for the multiple plugging connections. The SKEDD contact is designed such that it does not deform in the plugging process. The contact forks always adapt elastically to the PCB; there is no intermetallic bond between the SKEDD contact and through-hole. Only designed this way can multiple plugging and releasing be achieved. Simple and reliable on both sides Now to combine the SKEDD direct plugging contacts, on the PCB side, with the cable termination. The connection to the cable also uses a reliable and simple process, this was the idea with which Würth Elektronik eiSos realized as branding a new REDFIT IDC SKEDD plug connector would satisfy the market demand (Picture 2). Only officially available since 18 September 2017, it has already proven itself in its first application – as a debugger plug connector without a jack. The connection of the debugger to the microcontroller is crucial in the development of loading firmware, checking code, and detecting errors. “Usually a jack is soldered on the board to plug the debugger to the board,” Günther Klenner, Engineering Manager at K&K Prime Engineering, explains the approach. This jack is generally only used once, takes unnecessary space with a moderate package height and cost money for the additional components, procurement logistics,

Picture 1: Vertex (a) and arms (b) of the SKEDD contact are designed such that on plugging and releasing it accurately adapts, but does not plastically deform (c). Picture 1c Picture 1a Picture 1b

and insulation. “In large-scale production, microcontrollers are programmed prior to assembly. With the new plug, Würth Elektronik eiSos now offers a cost-effective way of carrying out the firmware upload retroactively, with a smaller series,” Klenner highlights the essential difference that he not only appreciates as a customer, but also enabled to some extent in his role as an external advisor for Würth Elektronik eiSos. As the plug enables reliable contact without any further tools or holding devices, the firmware can be loaded quickly and easily to increase efficiently in the production team. The plug is also protected against reversing polarity (Picture 3) and thus protects the debugger and microcontroller against damage due to incorrect contacting. In this context, Klenner goes on to point out another one of the plug connector’s interesting features: “The plastic guide is longer than the contacts.” This avoids shorts prior

to contacting or on the underlying mounting plate. Don’t understand: “Last but not least, there is no clearance requirement above the board, as the plug is pulled out again following the firmware update,” Klenner explains the benefit for the housing designer. How the REDFIT IDC SKEDD plug connector is used in a 2-wire debugger or as a 4-pin debug plug is explained in an AppNote (ANE004) that can be accessed at www.we-online.de/ downloadcenter. Responding flexibly to customer requests The new REDFIT IDC SKEDD can offer far more than debugging, it can also be a more permanent solution in the case of signal transmission. Users from the Measurement and Control Technology (MSR) field, it opens up an easy way for adapting devices to customer requirements without great cost. The provider of a measuring device has its base PCB produced with four SKEDD connection options where; the

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