TPS63020: Any suggestion of TPS63020 200Mhz EMI RE Issue

Hi   Wenchi,

       Have you done a comparison test with different dim duty?

Yeah, above situation as the highest brightness. When we turn down the brightness it's will not cause such high level EMI noise.

Hi   Wenchi,

       ok, is it possible add a RC snubber at node L1/L2? or add magnetic beads after output cap?

you can see there already add a RC at  node L1, even add an other C=1000p at node L2 it will lower the radiated level but still have the 200Mhz broad band noise.

Do the 200Mhz noise is the fetures of this series buck model?

Hi  Wenchi,

      Yes,  When the on/off state is switched,  high-frequency DU/DT DI/DT signal will be formed, and its multiple harmonics may be the noise source of 200Mhz. But i really do not know how it coupled out.

Regards

Tao

Thanks, Mr Zhang

Normally, we know the buck circuit will have the swithc noise, but less chance to see such a high frequency issue. That's the reason I am looking some opinion on here.