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Not Answered REF2025 and LM4132 - initial accuracy

Hirotaka Matsumoto
Guru 27525 points
Other Parts Discussed in Thread: REF2025, LM4132

Hi all

Would you mind if we ask REF2025 and LM4132?

About initial accuracy, as time of energization passes, does this initial accuracy change?
(According to passage of energization time, does accurancy value change?)

Kind regards,

Hirotaka Matsumoto

  • 0
    Guru 27525 points

    Hi team,

    We guess that your days are so busy, however could you let us know the reply?

    Kind regards,

    Hirotaka Matsumoto

  • 0
    TI__Intellectual 1745 points

    Hi Hirotaka,

     

    Initial accuracy is a measure of how close the reference voltage is to the expected voltage.  As time passes in an energized circuit, the change in the reference voltage is determined by the long term stability specification. 

    The REF2025 has an initial accurary maximum of +-0.05%, which translates to no more than 1.25mV difference from 2.5V initially.  As time passes, the part is specified to have 60ppm of drift long term (1000 hours).  So, after 1000 hours, the part will be within:

    2.5V +- 0.05% +-60ppm, or between
    (2.5V *(1-0.0005) * (1-0.00006))  and (2.5V *1.0005) * (1.00006), which calculates to between
    2.4986V and 2.5014V, or within 1.4mV of 2.5V

    The LM4132 has the same initial accuracy, with lower long term drift of 50ppm instead of 60ppm, and is within 1.375mV of a 2.5V reference after 1000 hours.

    Hope this helps you.

    Chris

  • 0 in reply to Christopher Dean
    Guru 27525 points

    Chris san,

    Thank you for your reply and your cooperation!
    We got it , however we would like to confirm one point.

    The LM4132's datasheet shows Long-Term Stability 0-1000 hours 60ppm. 
    So, even if the time passes 1000hours, Long-Term Stability is the same as 60ppm, isn't it?

    We do need your help.

    Kind regards,

    Hirotaka Matsumoto

  • 0 in reply to Hirotaka Matsumoto
    TI__Intellectual 1745 points
    Hi,

    The only long term specification is 1000hours, but after than you should still use the 60ppm number. The difference is that it is no longer guaranteed after 1000 hours since it is not tested.