[moved] How to solve harmonics on the SW pin of DCDC?

[loveelectronics.net]

The designed input range is 20~30V, the output voltage is 7.4V, the switching frequency is 500KHZ, and the maximum current is 20A.
In actual test, the input voltage is 25.3V, the VCC pin is 7.55V (the theoretical value of the specification is 7.5), the FB pin is 0.801V (the theoretical value of the specification is 0.8V), and the VOUT pin is 7.34V. However, the SW measured the resonance of the foot, which is very strange. I would like to ask if you have encountered this situation, do you know what the reason is?

 

[KlausST]

Hi,

show your circuit. (not one form any datasheet)

SW pin usually is the SWITCH pin. If so, then don´t suppress harmonics.

However, the SW measured the resonance of the foot,

I don´t know what this means.

Klaus

 

[Easy peasy]

far more info needed for any sort of helpful answer ...