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OPA2189: Long Term Stability

user4975766
Prodigy 10 points
Part Number: OPA2189

Please tell us the Long Term Stability of OPA2189.

  • 0
    Guru 48395 points

    Really? over what long term are you interested? Even if data was being taken (not likely) the part being in sample mode would preclude actual measured data at this point (unless you had a time machine). 

    I will say that prior lab measurements on choppers over actual years indicate measured drifts are more likely due to the lab equipment. 

  • 0
    TI__Guru 67791 points

    The long-term stability of IC parameters is based to the parametric shift as seen during the lifetest (HTOL) of new products conducted in high temperature ovens. 

    In a case of specs centered around zero, or a mean value, like Vos, Vos Drift, Vref, AOL, etc., they may shift over 10-year life at 25C up to:

      +/-100% of the max (min) PDS specified value

      In a case of parameters specified as an absolute value like IQ, Slew Rate (SR), Isc, etc. they may shift over 10-year life at 25C up to:

      +/-10% of the max (min) PDS specified value

    Therefore, in case of OPA2189 with max initial Vos of +/-5uV and max drift of +/-0.05uV/C, they could shift by up to +/-5uV and +/-0.05uV/C, respectively.  This means, for example, if a specific unit had initial Vos of 3uV and drift 0.01uV/C, after 10 years of operation at 25C,  Vos could shift up to 3uV+/-5uV = 8uV or -2uV while offset drift could shift up to 0.01uV/V+/-0.05uV/C = 0.06uV/C or -0.04uV/C.  For more information, please see attached presentation.

    2352.Long-Term Stability.ppt

  • 0 in reply to Marek Lis
    Guru 48395 points

    This of course is a pretty conservative estimate - having long term drift as the full initial spec range. The actual unit by unit long term drift from initial 25C values are much lower for choppers. 

    There are not very many plots out there testing this over years, but here is one - sadly, this plot ended on the same date the guy died taking the data.

    https://www.renesas.com/us/en/www/doc/application-note/an1729.pdf

  • 0 in reply to Michael Steffes
    TI__Guru 67791 points

    Yes, Michael is correct that having a long-term drift match the full initial spec is a very conservative estimate and the actual parametric shifts are much lower especially in chopper amplifiers like OPA2189 where Vos error including drift is continuously corrected. However, these are maximum allowable shifts used in qualification of the product based on the HTOL test data and for that reason the only numbers we can confidently stand by short of revealing actual HTOL measured data for each new product, which by TI internal policy we are forbidden to do.

  • 0 in reply to Marek Lis
    Guru 48395 points

    I did also stumble across another measured data plot over 88 days in the LTC2058 - again, basically flat at initial value,