How should power circuit isolation be designed for a power DTU?

The design of the DTU power loop isolation must ensure safety and signal integrity. An isolation transformer with a 1:1 turns ratio, a withstand voltage of 3000VAC, and an insulation resistance greater than 100MΩ is used for coupling. A CML3225A-510T common-mode inductor is deployed on the secondary side to suppress common-mode noise. Signal transmission uses optocouplers (such as TLP281) or digital isolators (such as ADuM1410). On the PCB, the isolation area has slots with a width greater than 2mm to prevent creepage. It passes withstand voltage testing (1500VAC/60s) and insulation testing (500VDC, >100MΩ). This isolation design enables the system to pass safety certifications and improves immunity by 30dB.