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REF2125: REF2125 Long Tarm Stability

Hiroaki Yuyama TED
Expert 1410 points
Part Number: REF2125
Other Parts Discussed in Thread: REF5025

Hi, support team.

When burn-in REF2125, please tell me the proper temperature and time. 

7.2 Long-Term Stability
One of the key parameters of the REF2125 reference is long-term stability. Typical characteristic expressed as:
curves shows the typical drift value for the REF2125 is 30 ppm from 0 to 1000 hours. This parameter is
characterized by measuring 32 units at regular intervals for a period of 1000 hours. It is important to understand
that long-term stability is not ensured by design and that the output from the device may shift beyond the typical
30 ppm specification at any time. For systems that require highly stable output voltages over long periods of
time, the designer should consider burning in the devices prior to use to minimize the amount of output drift
exhibited by the reference over time

Best Regards,
Hiroaki Yuyama

  • 0
    TI__Mastermind 19470 points

    Hi Hiroaki Yuyama,

    Long-term stability burn in cycle for this for figure 24 on the REF2125 was done at 1000 hours at 25C. An improved burn-in would be 1000hr at 35C. This process be greatly expedited by using a higher temperature. Typically after the first 1000hr cycle, the device will experience a smaller long-term shift.

    This blog talks about long term drift using the REF5025 but the same applies for the REF2125. The general idea is to burn-in past the most non-linear section of the long-term shift because it has the greatest change.

    https://e2e.ti.com/blogs_/archives/b/precisionhub/archive/2014/02/20/ic-long-term-stability-the-only-constant-is-change

    If you like the performance the REF2125, the REF34xx family has similar performance but has more voltage options.

    -Marcoo

  • 0
    Guru 140200 points
    Hi Hiroaki Yuyama,

    directly after soldering the voltage reference onto the PCB, the die and the package is full of mechanical stress. There are also traces of gas and water vapor tapped in the package as result from the soldering. By other words, the voltage reference is in an mechanical imbalance and tries to return to a state of equilibrium. This is the main reason for the inital drift of output voltage directly after the soldering. The idea of burn-in is, to accelerate the time the chip needs to return to the state of equilibrium, by simply applying heat. The higher the heat the higher the Brownian motion of atoms and molecules and the faster the state of equilibium is reached.

    So, for a proper burn-in apply as much heat as the chip and the whole PCB can withstand, without becoming damaged and allow the burn-in process enough time to work. For a fully assembled PCB I would recommend a maximum burn-in temperarure of about 80°C. And the burn-in should last at least 1000 hours.

    Keep in mind that the "acceleration factor" in the Arrhenius equation depends exponentially on temperature. So, with a too low temperature the burn-in might not show any useful effect.

    Kai