• State Resolved
  • Locked Locked
  • Replies 4 replies
  • Subscribers 63 subscribers
  • Views 1064 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TPS23861 Detection range

Koen Vercammen62
Prodigy 100 points
Other Parts Discussed in Thread: TPS23861

Hello,

I need to change a existing POE-PSE design and replace the POE controller. I'm probably going to use the TPS23861 for this and we want to use it in the AUTO mode (and only use the I²C for monitoring)

The POE-PD that we are going to attach contains an 28.7kOhm detection resistor instead of the standard 25kOhm.

For the TPS23861 I find that the accepted resistance range is between 19 and 26.5kOhm and the rejected range is less than 15kOhm or more than 33kOhm.

So it is not in the accepted or the rejected range, will the device accept this and power the device in AUTO mode ?

Thanks,

Koen

  • 0
    TI__Genius 12380 points
    Hi Koen,

    Welcome to the E2E forums and thank you for considering TI products for your design!

    Our entire team receives an email whenever a question is posted on E2E. Our specialist for PoE PSE equipment will respond soon.

    Thanks!
    Alex
  • 0
    TI__Genius 15655 points

    Hi Koen,

    19kohm ~ 26.5kohm is the IEEE standard on the PSE side. We set the threshold something between 26.5kohm and 33kohm. 28.7kohm may or may not be accepted by our PSE depending on the tolerance of your resistor, the temperature and the cable length, and we can't guarantee the performance.

    To understand your application better, why do you choose 28.7kohm as the detection resistance? That would be not IEEE compliant. Do you own both side of the cable(PSE side and PD side)? and do you want your PD end equipment only work with your PSE switch?

    Best regards,

    Penny

  • 0 in reply to Penny Xu
    Prodigy 100 points
    The 28.7kOhm was a bug in the first version of the devices it was fixed in the versions afterwards.

    So to be on the safe side we just need to say that those versions are not compatible then

    Regards,
    Koen
  • 0 in reply to Koen Vercammen62
    TI__Genius 15655 points

    Hi Koen,

    Thanks for the feedback. Your solution looks good to me.

    Best regards,

    Penny