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DP83867IR: IEEE 802 1000BaseT compliance Test failed

Michael Fauth1
Prodigy 40 points
Part Number: DP83867IR

Hi all,

i am currently in the verification process of a custom hardware design including the DP83867IRRGZ. During the ethernet 1000BaseT compliance tests according to IEE 802 i noticed, that we do not pass some of the mask tests and also the transmitter distortion test. We use a measurement setup from Rohde and Schwarz.

Find some examples of failing tests below:

This is an example of a mask test. The point where the mask is violated is slightly covered by the window in the top left:Mask

And the result of the transmitter distortion test as reported by the compliance tool:

TX Distortion

During the transmitter distortion test, the eye looks like follows which is not too bad i think. Are there any reference Screenshots available how the eye should look like?

Eye

I followed the process suggested in SNLA239A. Also i am aware of the troubleshouting guide SNLA246 and i checked everything included there.

At first i thought that the hardware on the MDI side of the PHY (e.g. ESD-protection, magnetics) might cause a problem. So i removed everything and added a 100 Ohm differential termination on the pads where usually the magnetics are. So the test setup contains only of the PHY, about 35 mm PCB trace and 4 100 Ohm termination resistors. The measurement results look absolutely the same which makes me wonder if there are any known problems with the PHY?

With best regards

Michael

  • 0
    TI__Genius 9920 points

    Hi Michael 

    For compliance testing we have noticed that some software tools may need to be updated to the correct formulas. For our compliance testing to match with UNH IEEE compliance results we use Tektronix

    Would it be possible to use other software and scope tools to test this or at least update your software?

    Thanks

    Cecilia

  • 0 in reply to Cecilia Reyes
    Prodigy 40 points

    Hi Cecilia,

    thanks for your response. I have only a Rohde and Schwarz scope available. The software running on the scope has been updated recently (about 2 months ago). What is the "UNH IEEE" you mentioned? What does the abbreviation UNH mean?

    I guess you don't know about any problems with the PHY in general?
    Could you provide screenshots of the eye diagram in testmode 4 (TX Distortion) to have some reference how it should look like?

    Best regards

    Michael

  • 0 in reply to Michael Fauth1
    TI__Genius 9920 points

    Hi Michael

    UNH is University of New Hampshire where the interoperability testing is performed to pass compliance. Your software tools should be able to share with you what the expected signals should be.

    Here is the report outlining 1000BASE-TX compliance testing written by UNH 

  • 0 in reply to Cecilia Reyes
    Prodigy 40 points

    Hi Cecilia,

    thanks. Can you please share the Test Report generated by your Compliance Test Suit?

    Best regards
    Michael

  • 0 in reply to Michael Fauth1
    TI__Genius 9920 points

    Hi Michael,

    I believe you'll need an NDA to review our test reports however most of the details of the test should be found in our application notes in regards to this as well as the report outlined in the pdf i had shared previously

  • 0 in reply to Cecilia Reyes
    Prodigy 40 points

    Hi Cecilia,

    i don't think that i need the whole test report. A reference how the eye should look like in testmode 4 for this specific PHY should be enough. This information is not available in any standard and also not in any TI application note as far as i know.

    However, an NDA should not be a problem. So please let me know what the required steps are.

    Michael

  • 0 in reply to Michael Fauth1
    TI__Genius 9920 points

    Hi Michael

    If you need a reference for what test mode 4 should look like this is a sample from the tektroniks scope I mentioned earlier which should show you the different test waveforms. Let me know if this helps