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Our product has a hole on the metal panel for the USB2.0 type B port. However, due to the mechanic size variation, on some panels, the USB connector can't touch the panel at all. As indicated in the image, there is a gap between the USB connector and the panel which causes the USB port isolated from the panel. This brings a problem for ESD testing because the electrostatic on the USB shell was supposed to be discharged through the metal panel to the ground. When the USB connector cannot contact the panel, the electrostatic is accumulated on the USB port which makes trouble to the PCB.

To solve this problem, the idea I have is to put some conductive paddings, like copper foil, between the USB connector and the panel, but this makes the product looks ugly. Does anyone have a similar problem and how do you solve it? enter image description here

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Ross
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  • Usually this is done first and foremost for EMI reasons. The first hit if you Google "USB A connector emi gasket" is a $1 to $0.50 part that will do the job. – tomnexus Dec 07 '20 at 05:08
  • Is the USB connector metal shell floating, or is it connected to the device metal case via the screw, and are both connected to system ground at any point? – Justme Dec 07 '20 at 05:37
  • @Justme Currently the USB connector metal shell is floating while the metal case is connected with the system ground. That's why I'd like to make the USB connector in contact with the metal case. – Ross Dec 07 '20 at 21:53
  • Floating shell is not good. Check these topics https://electronics.stackexchange.com/q/290777/117785 and https://electronics.stackexchange.com/a/269313/117785 – Ale..chenski Dec 08 '20 at 02:35
  • How large is the production run and how many PCBs you have currently? It defines whether it is cheaper to either apply afterthought parts to ground it, or make a new version of the PCB where it is fixed with a connection to ground. – Justme Dec 08 '20 at 05:20

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A quick-and-dirty fix is to put conductive foam tape around the USB connector, and with careful fitting of the lid, it would not look bad... until the lid is removed and replaced.

A neater option would be to use a conducive foam USB-sized gasket, adhered to the case or PCB around the connector.

DrMoishe Pippik
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