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TPS55287-Q1: pre-sales support: how to use/design this part in a project if I2C is not available.

Tony Zhang
Prodigy 205 points
Part Number: TPS55287-Q1
Other Parts Discussed in Thread: TPS552872-Q1, TPS631010, TPS631000

Tool/software:

Dear Friend 

I am considering TPS55287-Q1 in a data acquisition project. want some pre-sales support about:

1. my project is a pure hardware design and no MPU,  I2C is not available.  Since this part has no FB pin, I am wondering how to use this part in such a project?

2. Can this part work with conditions:  Vin= 3.1V, Vout=3.3V?  From datasheet, I have an impression that INTVCC takes power from either Vin or Vout,  if the both sources have lower voltage than required INTVCC working level, the chip may not be able to startup.

Thanks

Tony

  

  • 0
    TI__Genius 14950 points

    Hi Tony,

    Thank you for reaching out. For non-I2C, we have TPS552872-Q1. What is the load current? Is it for automotive? I can check if there is more suitable device for this low voltage application.

    Regards,

    Mulin

  • 0 in reply to Mulin Yuan
    Prodigy 205 points

    Hi Mulin

    Thank you for reply.

    TPS552872-Q1 has FB pin, but it has the same concern of startup condition as TPS55287-Q1. as stated in datasheet, the chip requires 5V INTVCC to work.

    How can it startup when both Vin and Vout are much less than 5V such as Vin=3.1V, Vout=3.3V?

     

    Thanks

    Tony

  • 0 in reply to Tony Zhang
    TI__Genius 14950 points

    Hi Tony,

    When Vin and Vout are both smaller than 5.2V, LDO will not work. VCC will directly be powered by Vin or Vout. So device can still work. But I have concern that if there is heavy load transient, Vin might drop below UVLO. So I want to check if there is suitable low voltage buck-boost for your application. That's why I ask What is the load current? Is it for automotive? 

    You can check TPS631000、TPS631010/1.

    Regards,

    Mulin

  • 0 in reply to Mulin Yuan
    TI__Genius 14950 points

    Hi Tony,

    We have not seen an update from you for four weeks, so I assume the issue is solved.
    I close this thread now. If there is still something open, please reply and the thread will get opened again.
    If you have any other question or of the thread has been locked, please open a new one.
    Clicking the Resolved Button also helps us to maintain this forum.

    Regards,

    Mulin

  • 0 in reply to Mulin Yuan
    Prodigy 205 points

    Hi Mulin

    working load is about 500mA or so, load transient might be 1A above. 

    I don't have concern about UVLO caused by load transient,  because 1A above load transient in my application is considered as abnormal situation and requires a power cycle. 

    I am more concerning if the device can start-up and work reliably at Vin =3.1V and Vout =3.3V.  

    I don't see how it can start-up and work if INTVCC is powered by either Vin or Vout which is much less than 5V. it is obviously out of specification. 

    Thank you

    Tony

  • 0 in reply to Tony Zhang
    TI__Genius 14950 points

    Hi Tony,

    VCC UVLO threshold is 3V, so it is within specification. It can work with this condition.

    Regards,

    Mulin