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How do you ground a USB shield?
- Connect the SHIELD connection to GND through a resistor. This helps isolate it and reduces EMI and RFI emissions. Keep this resistor close to the USB connector.
- Provide a plane for the USB shield on the signal layer adjacent to the VCC plane that is no larger than the USB header.
Can USB cables interfere with each other?
As USB is a digital signal, no, interference will not cause the audio to change. But USB audio is normally delivered via isochronous data transfer (think UDP), a best effort non-error correction protocol.
Where do I connect my USB to shield ground?
At some point, your digital ground must connect to your shield ground. For EMI reasons, this single point should be close to your I/O area. This means it’s best to place your USB connector with any other I/O connectors around one section of the board and locate your shield to logic ground point at that location.
How does a USB 3.0 cable shield work?
A metal braid is required to enclose all the wires in the USB 3.0 cable. terminated to the plug metal shells, as close to 360° as possible, to contain EMI. it appears that this is a grey area but the sheild should be connected to both sides but not connected to ground in any way.
Where is the shield ground on a PCB?
If you have a metal enclosure, this will be your shield ground. At some point, your digital ground must connect to your shield ground. For EMI reasons, this single point should be close to your I/O area.
Do you have to connect Shield at both ends?
For this reason, the lowest impedance path should be connected to shield at BOTH ends. Yes, there will be ground loops, and noise will get coupled in, but it won’t matter. In the case of high frequency, multipoint ground is prefered. Check to see if the manufacturer of your USB chip specs out what you should use.