I have a PCB with a few USB and RJ-45 Ethernet connectors on one side. I'm quite confused as to how exactly I'm supposed to be hooking up the SHIELD pins on them though.
This is for a host device that will interface with peripherals. It is provided regulated 5V 10A power by an external PSU, and is intended to be used inside a vehicle.
I have found this question (Should chassis ground be attached to digital ground?) along with others which helped me somewhat, but I'm still confused. The accepted answer on that says to use mounting holes, but I'm not sure if I understand fully. I'm not sure if the mounting holes connect chassis/digital grounds together directly or if they only connect to the metal enclosure. I assumed the later.
Even more confusing: What if I wanted to use a plastic enclosure? I'd prefer plastic, but I assume metal would protect it better against EMI inside the vehicle.
Here is a (very simplified) example of my current layout.
And the schematic (just in case, not really useful)
- The shield pins connect to the CHASSIS plane which is isolated from digital GND. The physical housing for the connectors should also be touching the metal enclosure as well.
- The CHASSIS plane is connected to the metal enclosure via the mounting holes/screws.
- The power supply GND is connected to the metal enclosure via the lower left mounting hole. This in turn connects GND to CHASSIS via the metal enclosure itself.
Am I overthinking this? Should I just connect the shield pins to GND and call it a day?