Do edge-box M.2 SSDs require separate EMC protection?

The edge computing box's M.2 solid-state drive (PCIe Gen3) with a speed of 8GT/s generates high-frequency radiation during operation, and the large transient current of the power supply can cause the overall radiation emission to exceed the standard. Therefore, separate EMC protection measures are required:

1. Connect a PBZ1608E600Z0T ferrite bead in series with the 3.3V power pin of the M.2 socket. Its DCR is 0.05Ω and its rated current is 2A, which can suppress power supply noise.

2. Connect a CMZ2012A-900T common-mode filter in series with the PCIe differential line. Its naming is CM common-mode, Z impedance is 2012, size is 2.0×1.2mm, 900T impedance is 90Ω, and 100MHz is placed close to the CPU.

3. Apply copper plating to the bottom of the M.2 module and densely cover it with grounding vias for heat dissipation, while also enhancing shielding.

4. Apply conductive cloth to the corresponding M.2 location on the overall structure and connect it to the outer shell.

Actual measurements showed that the unprotected edge box exceeded the 1.2GHz radiation standard by 6dB; after protection, the margin was 5dB.