DP83867IR: DP83867IR Connection to External Magnetics

William Schofield

Part Number: DP83867IR

I would like to interface the DP83867IR with the following GbE transformer http://productfinder.pulseeng.com/products/datasheets/H5120NL.pdf. How should I connect the center tap pins on the transformer. I have seen on the eavaluation module that the center tap pins are connected in the following way.

In this application note for a different TI GbE PHY the center tap pins are connected in the following way with the center tap pins connected to 2.5V

Which is correct?

over 8 years ago

0 Ross Pimentel over 8 years ago

TI__Mastermind 23675 points

Hi William,
If you are using the DP83867, you will need to use the recommended layout for that specific device.
Some devices have different line drivers so you need to follow the guides in the datasheet and application notes for the designated components.
Kind regards,
Ross

0 William Schofield over 8 years ago in reply to Ross Pimentel

Prodigy 60 points

Hi Ross,
There is no recomendation as to what should be done with the center tap pins in the DP83867 datasheet. There is only figure 28 in section 9.2.1.1 and the center tap pins are ommitted. The only clue is the schematic for the evaluation board which I'm not sure I can rely upon as a reference as the schematic looks as though it has been pieced together from several different sources.

0 Ross Pimentel over 8 years ago in reply to William Schofield

TI__Mastermind 23675 points

Hi William,

The center taps must be tied to ground through 0,1uF caps.

Center taps should not be tied together. They should be isolated away from each other.

Kind regards,

Ross

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DP83867IR: DP83867IR Connection to External Magnetics