How to troubleshoot excessive conducted interference (CE) from power supplies in data center switches?

Four-step method for troubleshooting conducted interference (CE) exceeding limits in the 0.15MHz-30MHz band of data center switch power supplies: Step 1: Use a near-field probe and spectrum analyzer to scan the power module to locate the noise source area, typically at a switching frequency of 65kHz and its octave peaks; Step 2: For differential mode noise exceeding limits in the 0.15MHz-1MHz band, increase the X capacitor from 0.22μF to 0.47μF; Step 3: For common mode noise exceeding limits in the 1MHz-30MHz band, add a CMZ7060A-701T common mode inductor (700Ω@100MHz) and increase the Y capacitor from 1000pF to 2200pF; Step 4: Optimize the PCB layout, adding an RC snubber (10Ω + 470pF) to the DS terminals of the switching transistors. After the rectification, the conducted interference margin was measured to be >6dB, meeting the EN55032 Class B limit.