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TPS3838: trip point

Viktorija Cecil
Mastermind 18491 points
Part Number: TPS3838

Team,

My customer currently uses our 3.3V , trips at 2.93 Supervisory chip TPS3838K33DBVT.

The question is:

  • Can they use 3.0V device that trips on 2.64V on a 3.3V rail (and still trip at 2.64V)? TPS3838L30DBVR

Thanks!

Viktorija

  • 0
    TI__Genius 9375 points
    Viktorija,

    You can use a resistor divider circuit to bring your 3.3V rail on Vdd down to the 3.0V that is required for the TPS3838L30DBVR. It is most likely the cleanest way to achieve this while keeping your trip point 2.64 as desired.

    Thanks,
    Abhinav.
  • 0 in reply to Abhinav.Sharma
    TI__Mastermind 18491 points

    I guess my question should have been:

     The spec says the device has a max rating of 6V.  If I start at 3.3V on a 3.0 device, it should

    a. handle the 3.3V

    b. trip at the desired 2.64 threshold, yes?

    Voltage divider doesn’t buy me any more head room, since the voltage of 2.7 on the supervisory chip will be 3.0 on the CPU chip.

    I wanted the CPU chip to start writing from 3.3V down to 2.7V with the supercap, but if the supervisory triggers at 3.0 (it thinks it’s at 2.7 with the voltage divider)

    then I have lost the same head room as if I just stuck to the 3.3 to 2.93V version I use now.

  • 0 in reply to Viktorija Cecil
    TI__Genius 9375 points
    Viktorija,

    I understand your question now. If you're looking for a part to trip at 2.64V, the "nominal supply voltage" listed will not matter. In your case, you can use the 3.0V option for your 3.3V part, and it will trip at the 2.64V listed in the datasheet. TI used to advertise our voltage supervisors as voltages monitored rather than threshold trip points, but this has changed since.

    To summarize, if my understanding is correct, you can use the 3.0V option and have your threshold stay 2.64 even if you use 3.3V on Vdd.

    Thanks,
    Abhinav.