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Technical Information
Overview of EMC Grounding (GND)
What is EMC Grounding?
EMC noise from digital circuits flows throughout PCB patterns, ground planes, power supply layers, as well as metal housings, and cables.
Grounding design is fundamental for both filtering and shielding and key for EMC management.
To suppress the noise flowing through the ground planes, noise filters convert unwanted noise into negligible heat and attenuate the noise.
For cable noise, conductive layer within cable shields should be electrically connected to frame ground (FG) or chassis ground.
To reduce impedance on PCB's, it is important to ground the board with multiple connections to the chassis at a short distance.
This provides a common potential for the circuit's signal lines and stabilizes operation for the return current flowing through the signal ground.
Unlike EMC filtering, grounding does not convert energy.
Instead, it reduces noise emissions by changing the flow of noise currents and stabilizing the ground.
It should be noted that changing the flow can potentially increase noise emission.
How to treat with High-frequency Noise by grounding
Previously, most problems occurred at frequencies below 500MHz but there has been a dramatic increase in challenges with higher frequency noise suppression.
This is due to technological advances in CPU processing speeds and increasing numbers of products equipped with wireless devices.
These cause a phenomenon known as "self-poisoning" or "internal interference," in which the device is influenced by its own emitted noise.
When using wireless or other high-frequency devices, it is recommended to prioritize the implementation of grounding solutions first and consider filtering and shielding afterward.