I am designing a PCB that would be powered by this PoE Module. The PoE module provides 5V output and drives a microcontroller, ethernet interface controller and other lower power circuitry. I do not see the power consumption to be more than 100mA.

The PoE module's datasheet recommends connecting the output pin (+V DC) and the ground pins to their respective signal planes to draw heat from the PoE module. I am designing a 2 layer board and I always make the top as well as bottom layers to be ground layers.

In order to draw heat from the PoE module, I created a polygon for the DC voltage output as shown in the figure below in the top and bottom layers and connected them using vias. Is this sufficient enough to draw heat from the boards? The polygon is about 0.5 sq.inch in size while the board is about 9 sq inch in size.

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1 Answer 1


Your power requirements are 500mW and This dc-dc converter is about 75% efficient, so you need to dispose of about 170mW of heat. That's unlikely to require any special treatment.

If you were wanting the full 12.5W out it would be worth considering.


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