DC/DC Buck converter drops voltage when connected to load.

[Pariston]

Hi,
I've been trying to use MAXM15065 buck converter for my project, but I faced difficulties setting it up. At 39 Volt input voltage, I get 3.3 volt output as expected. However, once load is connected, I get significant voltage drop to around 1.2 volt. This buck converter was connected according to datasheet, and all tests performed isolated from the rest of the circuit. I will also attach link to datasheet and setup layout.

https://datasheets.maximintegrated.com/en/ds/MAXM15065-MAXM15067.pdf

[brucehoult]

Presumably you're trying to pull more than 300 mA from it -- possibly much more but it's really hard to say as their output voltage vs current graphs don't go past the rated 300 mA and it might well drop off precipitously after that.

[Pariston]

I've tried connecting 220 ohm resistor as my load and ended up with 2.06 volt across it (9 mA)

[tooki]

Could you post your circuit? (Schematic and a picture of it assembled.)