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DP83867IR: EMI

Jack Li-SH
Expert 4455 points
Part Number: DP83867IR

Tool/software:

Hi team,

When Delta design the Ethernet PHY, DP 83867,   they selected  C6 package to 0805,  NOT 1206.  But there is no 0805 MLCC capacitor which can support up to 2KV,  then   2 pcs 0805 MLCC in series used.

The real circuit  as following used to replace C6 in the above:

Q1: Do you think  whether the above network will degrade  the Ethernet data performance, such as the eye diagram?

Q2:  Whether it will degrade EMI performance?   for example:  +/-4KV ESD etc.

Thanks a lot!

Regards,

Jack

  • +1
    TI__Guru**** 177846 points

    Jack

    The 1000nF is part of the Bob Smith Termination. A Bob Smith termination with a 1000pF capacitor is a standard circuit to manage common-mode noise and protect against static discharge. The capacitor coupled the high-frequency common-mode noise to ground while blocking the DC voltage.

    The proposed schematic deviates from the Bob Smith termination and this is something we have not tested before, so I can not comment is performance against common mode noise suppression and ESD performance.

    Thanks

    David