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LM5017MR Unregulated output voltage problem

Dear TI Team,

I'm designing an isolated DC-DC buck converter using LM5017MR. The input voltage is +12V till 48V and the isolated output should be 3.3V (primary winding output voltage: 4V).

However, the result from the PCB showed that the output voltage from primary winding and secondary winding are unregulated. With +12V input voltage, the output is 3.3V on the primary winding, and will increase as the input voltage to the IC is increased. I have checked again the schematic and the layout and I couldn't find anything that might disrupt the feedback path (since I suspected it is caused by wrong value for FB resistors or unconnected node in this path).

Could you please tell me where this might come from or the possible cause?

2100.LM5017MR circuit.pdf

5428.LM5017MR layout.pdf

Thanks in advance.

Sincerely,

Theresia Paramitha