TPS2378: PoE connection with RJ45 for ethernet 10/100

albgarc2014

Part Number: TPS2378

Hi TI,

I am designing a PoE powered 10/100 ethernet device with the TPS2378DDA controller.

The phy ethernet controller chip suggests a connection with RJ45 connector as the image A. But I think that through the 75 ohm resistors there will be an over consumption.
I have seen that in RJ45 1GB connectors with magnet and POE they use a capacitor in series with the 75 ohm resistor. My idea is to use these capacitors as in image B.
Would the schematic in picture B work, could I draw the voltage from the PoE without affecting the communication?

Thank you very much.

over 3 years ago

+1 Michael Pahl over 3 years ago

TI__Mastermind 21320 points

Hello,

The Ethernet PHY separates the power and data.

I can only speak for the power side. Please use the 0.01uF capacitor and 75 ohm resistor for the Bob-Smith terminations as specified in the following application note: https://www.ti.com/lit/an/slua469/slua469.pdf?ts=1616707427981&ref_url=https%253A%252F%252Fwww.google.com%252F

For the data side, please either use the PHY datasheet or contact your PHY vendor for how to terminate the PHY. If you are using TI, please create a thread and tag the PHY part, not the PoE part.

If this post answers your question, please indicate so by marking this thread as resolved. Thank you.

Regards,

Michael P.

Applications Engineer

Texas Instruments

0 albgarc2014 over 3 years ago in reply to Michael Pahl

Genius 3415 points

Hello Micheal,

Sincerely thank you very much.

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TPS2378: PoE connection with RJ45 for ethernet 10/100