Dp83848 damaged with poe

pablo tavolaro

Hi my circuit as follow

The circuit work properly is powered by DC IN 12V.
But sometimes when powered by Poe the DP83848 is damaged when plug the RJ-45
When DP83848 is damaged the temperature increases to 40ºC
and the impedance between GND and Vcc3 decrease to 65 ohms.
When this happen no more Ethernet connection and the link led is blinking.

If change the DP83848 the Ethernet link is established and all work fine.
What can damaging the DP83848?

over 9 years ago

0 Rob Rodrigues over 8 years ago

TI__Mastermind 19780 points

Hi Pablo,

In case other users find this thread.

The main problem I see in your schematic is that you do not have surge protection diodes between the magnetics and the DP83848. Transient voltage surges may damage the DP83848 when plugging/unplugging the RJ45.

Please see a similar issue and solution from this thread: e2e.ti.com/.../522510

Regards,

0 pablo tavolaro over 8 years ago in reply to Rob Rodrigues

Prodigy 170 points

Hi Rob

Thanks, we solved the problem using RCLAMP3304NATCT

regards

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Dp83848 damaged with poe