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TPS23841: Whichi is popular alternative A or B

Shinichi Inoue
Guru 21701 points
Part Number: TPS23841
Other Parts Discussed in Thread: TPS23861, TPS2388,

Dear Specialists,

My customer is considering POE system and has a question.

I would be grateful if you could advise.

---

POE(IEEE802.3 at) has a two types of alternative mode, A and B.

I think it is different from using twist pair cables.

Which is popular as a POE(IEEE802.3 at) power supply scheme?

---

I appreciate your great help in advance.

Best regards,

Shinichi

  • 0
    TI__Expert 5615 points
    Shinichi,

    Correct - the IEEE802.3at standard allows for 2 different wiring schemes. ALT-B is more popular in mid-span applications and has potential benefit for systems with either of the following 2 characteristics:

    * 10BASE-T/100BASE-TX limited systems (aka, switches which do NOT offer 1000BASE-TX operating capability): can potentially save the cost of a data transformer in this case
    * Power redundancy applications

    Otherwise, I would recommend you adopt the far more popular ALT-A wiring approach.

    Further, assuming ALT-A will suffice, I suggest to consider adoption of a newer PSE controller. There is nothing wrong with the TPS23841; however, the TPS23861 and TPS2388 are more recent releases and have better, overall, system support and design-in tools. We have a special note on the TPS23841 product folder with this same guidance.

    Please let me know if this reply is helpful and thank you for your interest in PoE products from Texas Instruments,
  • 0 in reply to Thomas Lewis
    Guru 21701 points

    Hi Thomas,

    Thank you for your reply.

    The customer is now considering a concept.

    I'll share your suggestions with the customer and proceed with consideration.

    I appreciate your great help.

    Best regards,

    Shinichi

  • 0 in reply to Shinichi Inoue
    TI__Expert 5615 points
    Shinichi, Thank you for the feedback.

    I am going to close this thread for now - feel free to start a "related" question should the customer have some follow-up questions later.

    Thanks,
  • 0 in reply to Thomas Lewis
    Guru 21701 points
    Hi Tom,

    Thank you for your reply.

    I agree to cloth this thread.

    If the customer has an additional question, I'll ask as a related question.

    I appreciate your great help.

    Best regards,
    Shinichi