DP83867IR: Center tap of the magnetics

Tawichai Premgamone

Part Number: DP83867IR

Hello,

I want to connect the DP83867IR (RGZ package) to an RJ45 with integrated magnetics. However, the capacitance values of the center tap of the magnetics is only 0.01 uF instead of 0.1 uF, recommened in the data sheet. As well, the capacitance at the cable side (connected to the R 75 ohm to Gnd) has value only 1 nF instead of 10 nF.

Are these capacitance vaulues still in the acceptable range?

Target RJ45 with integrated magnetics:

Recommended Diagram for DP83867IR:

Thank you very much.

over 7 years ago

0 Rob Rodrigues over 7 years ago

TI__Mastermind 19780 points

Hi Tawichai,

Your attachments/photos didn't come through. Do you have a link to the integrated magnetics schematic?

You should follow the recommendations in the datasheet for the PHY side magnetics closely. The cable side of the magnetics can be changed easier.

Best Regards,

0 Tawichai Premgamone over 7 years ago in reply to Rob Rodrigues

Prodigy 30 points

Hi Rob,

Here is the schematic of the RJ45 with magnetics.

Thank you very much

Best regards,

Tawichai

0 Rob Rodrigues over 7 years ago in reply to Tawichai Premgamone

TI__Mastermind 19780 points

Hi Tawichai,

The cable side, Bob Smith termination would be OK, but the center tap caps at .01uF are out of specification for the DP83867.

Please use the center tap configuration shown in the datasheet which was developed by characterization and design of the PHY.

Best Regards,

0 Tawichai Premgamone over 7 years ago in reply to Rob Rodrigues

Prodigy 30 points

Thank you very much Rob Rodrigues. I will find another socket.

Best regards,
Tawichai Premgamone

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DP83867IR: Center tap of the magnetics