Issues with PM8805 Overheating on Custom PCB – Need Assistance

[leeki33]

Hello ST Community,

I am currently developing a product using the PM8805 chip and have purchased and tested the STEVAL-POE001V1 evaluation board. Based on the reference design provided by ST, I created my own circuit diagram and manufactured a custom PCB. I then mounted the PM8805 chip on my PCB and began testing.

Unfortunately, I encountered a few issues during testing:

• The STEVAL-POE001V1 board stopped functioning during my tests.
• When I connected my custom PCB with the PM8805 chip to a PoE cable, the chip overheated almost immediately.

On the positive side, the LED indicated the device had reached T0 mode, so the device seems to be partially functioning.

I suspect there may be a misunderstanding in my design or implementation of the PM8805. I am attaching my circuit diagram and would appreciate it if someone could review it and provide feedback on whether any components or design elements might be unsuitable for the PM8805.

Any advice or suggestions would be greatly appreciated. Thank you in advance for your assistance!

[Peter BENSCH]

Welcome @leeki33, to the community!

Unfortunately I have only just seen your question, perhaps it is still relevant?

You described the behaviour of your board, but not the results when using the EVAL. Were they identical?

What does your layout around the PM8805 look like?

Regards
/Peter