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TPS23730: Compatibility with TPS23731

ArTzy
Genius 17625 points
Part Number: TPS23730
Other Parts Discussed in Thread: TPS23731

Hi Team,

Good day. I have this query about TPS23730 as replacement over TPS23731. The question is if it can be done without connecting pin 20 of the 23730. Pin 20 is NC on the 23831 and the board doesn't connect it. Any affect on current design?

Thank you for your support.

Regards,

Archie A.

  • 0
    TI__Mastermind 21320 points

    Hey Archie, 

    These parts have same footprint, only a few extra pin functionality for the TPS23730. 

    Here are the extra pins and how to disable them to use the TPS27330 in a TPS23731 design. 

    pin 31: DT-- connect to VB

    pin 20: CLSB -- you can leave it open

    pin 19: PPD -- tie to VSS or float

    pin 18: SCDIS -- leave open

    pin 12: BT -- you can leave open

    Pin 13 and Pin 14 are indicators, so they are connected the same way but have different functions

    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
    TI__Genius 17625 points

    Hi Michael,

    Thanks for your support. I have here some follow up questions.

    May we know how the device TPS23730 behave in Class 0 or 3? Class 0-3 devices theoretically don't use the second classification current. This is what my client wanted to confirm.

    Thank you.

    Regards,
    Archie

  • 0 in reply to ArTzy
    TI__Mastermind 21320 points

    Hey Archie, 

    It behaves the exact same. The power level does not have an impact on the performance of the IC (besides like thermals because of current through the internal FET, but those are better at lower power levels). 

    Specifically for the second classification current ---- the class current is driven by the PSE, not the PD. So if the PSE identifies a class 0-3 device, it will stop the PoE handshake and send the power. So the TPS23730 state machine that turns on the second class pin (CLS_B) does not enter that state so it never turns on. So you can either put a resistor of equal value or just leave the pin floating. 

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

     

    Regards, 

     

    Michael P.

    Applications Engineer

    Texas Instruments