• State Resolved
  • Locked Locked
  • Replies 2 replies
  • Subscribers 40 subscribers
  • Views 130 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.

PMP9563: Switching FET difference between PMP9563 and TPS23734EVM-094

Shinichi Inoue
Guru 19741 points
Part Number: PMP9563
Other Parts Discussed in Thread: TPS23734EVM-094, TPS23754, TPS23734, TPS23730EVM-093

Dear Specialists,

My customer is considering PMP9563 as a reference.

They have a question about switching FET between PMP9563 and TPS23734EVM-094.

I would be grateful if you could advise.

---

The PMP9563 uses the FDS86242 as the switching FET.

On the other hand, the recommended FET of the new product TPS23734EVM-094 is FDMS86252.

The FDM86252 has a higher rated current and lower ON resistance, so I think it is a higher-end product.

The TPS23734 is a new device that supports up to IEEE 802.3b, but the PD power level is 13W and 25W, and there is no difference between the TPS23754 and PD power level.

What is the reason for using the higher performance FET (FDMS86252) in TPS23734?

Is there any problem to use FDS86242 for IEEE802.3at PD Class 4 (25.5W)

---

I appreciate your great help in advance.

Best regards,

Shinichi

  • +1
    TI__Mastermind 21320 points

    Hey Shinichi, 

    Thank you for your question. 

    The customer can certainly use the lower rated FET since this design is only 25W. 

    We use the higher rated FET because the TPS23734 EVM was actually built on the TPS23730EVM-093 layout file. Since we require the higher rated FET in that design, we kept it in lower power design since it will have higher rated performance and save time compared to finding an equivalent FET in the same package with all the appropriate ratings. 

    Additionally, just to clarify, the TPS23734 is for 25W as you said but also the new IEEE802.3.bt standard. What that means is the TPS23734 can negotiate 25W of power over 4 pairs of ethernet cable, vs older generation parts can only negotiate over 2-pairs. This means overall better system efficiency.

    The other difference is the TPS23734 has a feature called Auto-MPS ----- this feature sends current pulses to meet MPS signal requirements. The current level is different between .at and .bt spec --- so the TPS23734 can automatically detect the PSE type and send the appropriate MPS signal current level.

    If this post answers your question, please indicate so by marking this thread as resolved. Thank you.

     

    Regards, 

     

    Michael P.

    Applications Engineer

    Texas Instruments  

  • 0 in reply to Michael Pahl
    Guru 19741 points

    Hi Michael,

    Thank you for your reply and helpful information.

    I understand TPS23734EVM-094 uses TPS23730EVM-093 layout and uses the same FET package drawing.

    Also I understand the difference between TPS23734 and TPS23754.

    I'll share these information with the customer.

    I appreciate your great help and cooperation.

    Best regards,

    Shinichi