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How to connect USB connector shield on PCB?
Should it be connected to GND plane right where USB is placed, or should the shield be isolated from GND, or should it be connected to ground through ESD protection chip, high resistance resistor or fuse? PS. Should I put the shield connections on schematic, or just route it on PCB?
Where does the ground Plance stop on a USB shield?
You can see that the ground plance stops short of the USB socket. The large hole is where the tabs for the USB shield to have a mechanical connection to the PCB. R1 is then connecting the shield to GND, and capacitor C3 is doing the same on the other connection.
Where is the GND trace on a USB shield?
The location of the Chassis to PCB GND tab is on a sub-PCB, with a 30thou trace to the tab. (yes, I know it sounds strange, but the space constraints were ridiculous and this was not my design!) Firstly (as a bit of a cop out) personally, in designs I always ground through a 0R resistor so that the decision can be changed.
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.
How to connect USB shield to signal ground?
Here are some of the options that have been recommended. only. (1) Connect shield directly to signal ground. connector shell be tied to the ground plane. Intel. EMI Design Guidelines for USB Components. Sec 5.4 (p. 9). (2) Connect shield to signal ground through a capacitor. (Possibly with high-value parallel resistor approximately 1 Mohm.)
How is a shield connected to a chassis?
For connectors with a shield, that shield is connected to the metal chassis through as short of a connection as possible. Ideally the connector shield would be touching the chassis, otherwise there would be a mounting screw on the PCB as close to the connector as possible.
Where does the ESD go in a PCB?
You may or may not be over thinking this, it depends on what your application is, and if you have to pass any regulatory inspections for a product. The general idea is to shunt the ESD to ground through the chassis and away from your electronics. This depends on if your enclosure is insulated or not.
What happens if I connect my shield to ground?
The danger of directly connecting your shield to ground is that if two devices have “grounds” at different potentials and there is significant DC current capability from those sources, this connection could serve as a fuse between the two power systems.