[LT4293/DC2911A] PoE bt compliance test fail

To whom may it concern,

Hi i'm HS.

I conducted the bt compliance test with DC2911A via Sifos PDA604-A and found out two parameters are failed as you see below.

Red box on the left is the measured value and the blue box is the expected range of normal value.

Please see the description of these two parameters below.

Please share you opinion on this with me.

Thank you!

  • +1
    •  Analog Employees 
    on Apr 12, 2021 8:13 PM

    Hi HS,

    IEEE 802.3bt introduces a new optional feature, Autoclass. Autoclass enables the PSE to reclaim power budget from single-signature PDs requesting more power than needed under worst-case operating conditions. ADI's IEEE 802.3bt PSEs support Autoclass, while ADI's current IEEE 802.3bt PDs do not support this optional feature. Autoclass is only useful for applications where the full load can be drawn on demand and shortly after turn on.

    For the Sifos PDA-600 compliance tester, there is an option to tell the testing software whether this PD supports Autoclass. Set this to "No" before testing the LT4293.

    Also, with your current result from Sifos the description points out this is optional behavior:

    Please refer to our LTC4291-1/LTC4292 datasheet for more information on Autoclass.

    Best Regards,

    Eric