MP8008 PoE Feedback Circuit reference voltage

Hi everyone!
I’m new to the forum and to PoE circuit design in general.

I tried copying the reference design for MP8008 and adjust it to output 5V instead of 12V.
I replaced the transformer with a Wurth 750310744 and updated the resistor values for the voltage divider in the feedback circuit (R1 & R2, now both equal to 191kΩ).

Whilst doing this I had a doubt regarding the TL431 used in the reference design for the 2.5 V reference voltage: according to the footprint of the MP8008 evaluation board (EV8008), it seems like the pin configuration of the component mounted doesn’t match the schematic - the cathode and ref pins seem to be swapped.

Is it me being silly or is there an actual error in the evaluation board BOM? The TL432 seems to be matching the PCB layout instead.

Any help would be appreciated!

1 Like

Hi Nzapponi,
You are correct, the TL431 is called out in the schematic and BOM but the TL432 2.5V part is used in the eval board. Thank you for catching this.
Regards,