AdvancedTopic 97 of 104Electronics & Embedded
Electromagnetic interference mitigation
Shielding, filtering and layout reduce emissions and susceptibility.
In depth
Reduce emissions with smaller current loops, ground planes, spread-spectrum clocking, slower edges, filtering (ferrites, common-mode chokes), shielding and proper cable handling. Pre-compliance scans identify problems early. Immunity requires TVS, filters and robust firmware.
Key points
- Common-mode vs differential-mode
- Return paths
- Shield terminations
ExampleAdding a ferrite bead on a USB cable cuts radiated noise.
What is Electromagnetic interference mitigation?
Shielding, filtering and layout reduce emissions and susceptibility.
Why is it important to understand electromagnetic interference mitigation?
EMI can make a product fail regulatory tests or disturb other equipment, so shielding and filtering are designed in from the start.
What is conducted emission?
Noise that travels along cables and power lines, measured on the mains side and tested against standards.
Why does a loop area matter?
Large current loops radiate more, so keeping signal and return paths close together reduces emissions.
How is Electromagnetic interference mitigation used in practice?
Typical applications include adding a ferrite bead and capacitor to a power line to reduce conducted noise, shielding a high-frequency oscillator in a metal can and routing high-speed signals over solid ground planes to reduce radiated emissions.
What should I learn before Electromagnetic interference mitigation?
Study "Signal integrity" first (topic 96 of 104 in Electronics & Embedded). It covers the groundwork this topic builds on.
What are the key points of Electromagnetic interference mitigation?
Common-mode vs differential-mode. Return paths. Shield terminations.
Can you give an example of Electromagnetic interference mitigation?
Adding a ferrite bead on a USB cable cuts radiated noise.
What comes after Electromagnetic interference mitigation?
The next topic is "Analog-mixed-signal design", which builds directly on this one.
How difficult is Electromagnetic interference mitigation?
It is classed as Advanced in Electronics & Embedded (topic 97 of 104). It is an advanced topic. It assumes you are comfortable with the intermediate topics in Electronics & Embedded.