DP83825I: Query on TIDA-010046 reference design

Elbin Thomas

Part Number: DP83825I
Other Parts Discussed in Thread: TIDA-010046

Hi Team,

I was going through the TIDA-010046 reference design and noticed that the media side of the Ethernet magnetics is connected to the side without the common-mode choke (CMC), while the CMC side is connected to the PHY. I also observed that the HX1198FNL datasheet recommends the same connection.

However, the LP2019ANL datasheet suggests the opposite arrangement, where the media side is connected to the CMC side of the magnetics.

Is there any specific reason for this difference in the recommended connection? Are there any performance, EMC, or signal integrity considerations behind these different implementations?

Best Regards,

Elbin

20 days ago

+1 Shane Hauser 20 days ago

TI__Mastermind 37875 points

Hi Elbin,

There should be no major difference between having the CMC on the PHY-side or connector-side of the transformer as far as I am aware. I have seen one case where a CMC was recommended to be placed on the PHY-side to better protect it from transient voltages, so if ESD is a concern you may opt for a transformer with a PHY-side CMC.

As for why this recommendation is different in the magnetic datasheet it may be better to ask the magnetics manufacturer.

Best,

Shane

0 Elbin Thomas 20 days ago in reply to Shane Hauser

Prodigy 100 points

Hi Shane,

Thank you very much!!!

Best regards,

Elbin

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DP83825I: Query on TIDA-010046 reference design