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UC1825A-SP: UC1825A-SP 1.25V internal voltage

Jason Nguyen84
Intellectual 355 points
Part Number: UC1825A-SP

I am looking for the tolerance variations  (initial tolerance , temperature, aging, radiation) of the 1.25 V internal which connects to the RAMP pin. Beside the 1.25V could impact the current limit, is there any internal parameters within the PWM IC could cause impact on current limit ? 

  • 0
    TI__Mastermind 20045 points

    Hello Jason,

    We do not have data on the actual offset voltage itself. However, we have data showing the error amplifier output which should be the same as the 1.25V offset due to the virtual short between the pins. You can find the radiation data concerning this parameter on page 48 of the radiation report at www.ti.com/.../snaa272.pdf.

    Over temperature we have measured the following. Note that these are our samples that we measured and are not guarantees.

    Minimum measured Typical Maximum measured
    25C 1.162 1.218 1.253
    125C 1.131 1.162 1.192
    -55C 1.116 1.143 1.162

    I will see if we have any data related to lifetime or other internal parameters.

    Thanks,

    Kyle

    TI makes no warranties and assumes no liability for applications assistance or customer product design. You are fully responsible for all design decisions and engineering with regard to your products, including decisions relating to application of TI products. By providing technical information, TI does not intend to offer or provide engineering services or advice concerning your designs.

  • 0 in reply to Kyle Rakos
    Intellectual 355 points
    Hi Kyle,

    I could not open the snaa272.pdf file. Could you send the rad data for me jason.nguyen@microsemi.com

    Thanks
    Jason
  • 0 in reply to Jason Nguyen84
    TI__Mastermind 20045 points
    Hi Jason,

    Sorry, a period was placed at the end of the URL. You can remove the period or try again: www.ti.com/.../snaa272.pdf

    I can send an email if it still doesn't work.

    Thanks,
    Kyle
  • 0 in reply to Kyle Rakos
    Intellectual 355 points

    Hi Kyle,

    Sorry for late response,  I was out on vacation. Yes, I am able to review the Rad data. Is there any way we could predict how much variation on this 1.25V parameter due to aging effect ?

    Thanks

    Jason

  • 0 in reply to Jason Nguyen84
    TI__Mastermind 20045 points

    Hello Jason,

    I was able to obtain the following data from our life tests. I have emailed the results to you (sorry for the confusion of the previous post).

    Please let me know if you need anything else.

    Thanks,

    Kyle

    TI makes no warranties and assumes no liability for applications assistance or customer product design. You are fully responsible for all design decisions and engineering with regard to your products, including decisions relating to application of TI products. By providing technical information, TI does not intend to offer or provide engineering services or advice concerning your designs.

  • 0 in reply to Kyle Rakos
    Intellectual 355 points
    Kyle

    Thank you very much

    Jason Nguyen
  • 0 in reply to Jason Nguyen84
    TI__Mastermind 20045 points
    Hello Jason,

    Glad I was able to answer your question. I had to remove the data on the post but I emailed it to you for your reference.

    I also just want to point out that on the datasheet it says, "Current limit threshold is assured to a tolerance of 5%". This 5% is due to the internal device variation and could potentially be greater due to external component variation. See Icl under electrical characteristics for how this value was determined.

    Thanks,
    Kyle