I got a buck converter from Amazon. This- https://www.amazon.com/MCIGICM-step-down-Converter-3-0-40V-1-5-35V/dp/B06XZ1DKF2
Now it's soldered onto a custom PCB I designed. I'm supplying it with 12V and the output is set to 5V. Total power in and out of the system is about 9W.
As soon as I start pulling power from the chip, it emits a horrible screeching sound, something in the high 10kHz range. That makes sense because it might be noise from the inductor, but here's the kicker: If I desolder the same buck convertor and instead of soldering it directly to the board, attach it using jumper wires; the sound disappears. I can also duplicate this problem with the exact same results with all the buck converters I received and it's breaking my mind a little
Any clue why? I'd like to have the chip soldered on and not floating in the air. Any suggestions on how to get out of this mess?