How to improve EMC performance of power FTU multilayer boards?

Multilayer boards improve EMC performance through optimized stack-up design. An 8-layer stack-up is recommended: L1 (signal), L2 (ground), L3 (signal), L4 (power), L5 (ground), L6 (signal), L7 (power), and L8 (signal). Key principles: Each signal layer should be adjacent to a ground plane with a layer spacing of less than 0.2 mm; the power plane should be tightly coupled to the ground plane with a spacing of 0.1 mm. High-speed signals are placed on inner layers (L3, L6), while low-speed signals and power are placed on outer layers. The ground plane should be intact without any splits, while the power plane should be appropriately segmented. This stack-up design shortens the signal return path, reduces radiated emissions by 15 dB, and improves immunity by 20 dB, meeting the testing requirements of IEC 61967-2 and IEC 61000-4-3.