5 Tips for Improving EMC Performance with MORNSUN Modules

Electromagnetic Compatibility (EMC) is a critical aspect of electronic design. While MORNSUN modules are designed with excellent EMC performance, proper implementation is key to passing compliance testing. Here are five tips from our FAEs.

1. Use the Recommended External Circuit

The datasheet for most MORNSUN modules provides a recommended peripheral circuit for meeting specific EMI standards (e.g., Class A or Class B). This circuit, often consisting of capacitors, inductors, and common-mode chokes, is crucial. Do not omit it to save cost; it will likely cost more in re-testing and debugging later.

2. Pay Attention to PCB Layout

Keep the loop area of high-frequency switching currents as small as possible. Place input and output capacitors as close as physically possible to the module's pins. Use a solid ground plane to provide a low-impedance return path for currents.

3. Ensure Proper Grounding

Connect the 'FG' (Frame Ground) pin of enclosed power supplies directly to the system's chassis ground with a short, low-impedance connection. This is vital for shunting common-mode noise away from your circuits.

4. Isolate Noisy and Sensitive Components

Physically separate the power supply and its switching components from sensitive analog circuits or high-speed digital lines on your PCB. If they must cross, ensure they do so at a 90-degree angle on different layers to minimize coupling.

5. Use Shielded Cables

For input and output connections that are routed off-board, use shielded cables. Connect the shield to the chassis ground at the power supply end to provide a path for noise to be diverted away from the load.