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TPS54060-Q1 / TPS54160-Q1 Enable reference tolerance

Thomas LE BIVIC
Intellectual 510 points
Other Parts Discussed in Thread: TPS54060

Hi all,

I'm working with the TPS54060-Q1 and the TPS54160-Q1 and I'm very suprised of the poor accuracy of the Enable reference voltage : 0,9V < 1,25V < 1,55V. And this is given at 25°C with no indication in the [-40;+85] range.

I'm trying to make a 12V DC/DC which will start when Vin > 12V and will not stop before Vin goes below 16V. Calculating worse cases it seems impossible.

However, on existing boards with TPS54060-Q1, the reference voltage seems close to 1.25.

Any advice ? Should I accept to have my 12V DC/DC that may start when Vin = 8V to be sure that it will still be ON at 16V ?

Thanks.

  • 0
    TI__Guru**** 191445 points

    There is an updated "A" version of these devices with better tolerance on the EN threshold.  I am reasonably certain the start threshold is always higher than the stop threshold.

  • 0 in reply to JohnTucker
    Intellectual 510 points
    Hello John, thank you for you answer,

    I didn't want to change the component for now. I agree with you that for each board, Uon is always higher than Uoff, the problem is with worse cases : to ensure Uon > 12V : worse case Uoff = 22V which is not acceptable in my design. My requirement for Uoff is more important than the one for Uon so I think I'm gonna lower ther voltage threshold.

    Any advice for startup in Vin < Vout(expected) condition ?
    Vout will follow Vin rise while Vin < Vout and that's it ? Any limit for Vin minimum rise time ?

    Thanks for you support,

    Thomas
  • 0 in reply to Thomas LE BIVIC
    Intellectual 510 points
    If it is not safe to start with Vin < Vout(expected), I'll go for an external comparator driving EN in a binary way ;)
  • 0 in reply to Thomas LE BIVIC
    TI__Mastermind 35185 points

    Hi Thomas,

    You may see non monotonic start up behavior on the outputs of the TPS54060/160 if the input voltage ramps up very slow in comparison to them. However in your application if you have the flexibility to set the startup time of the input supply and the startup time of the TPS54060/160 output, you could design it such that the input supply always ramps up faster than the TPS54060/160 output.

    If you won't be able to design it this way, the external comparator with a more accurate threshold would be the most robust solution.

    Best Regards,
    Anthony

  • 0 in reply to Anthony F
    Intellectual 510 points
    Thank you very much for this detailed and inspirational answer (start-up timing configuration : simple and efficient, I should have though about it !)

    Best Regards,
    Thomas
  • 0 in reply to Anthony F
    Intellectual 510 points
    Oh ! One last question : any idea of Min/Max ENABLE REFERENCE in the [-40°C/+85°C] range ?