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REF70: initial accuracy

Mia Ma
Intellectual 2325 points
Part Number: REF70

Tool/software:

Hi team, 

For our REF70 or total reference series, there is the initial accuracy spec in the datasheet: High accuracy: ±0.025% maximum

Here is one curious item for our REF70, for the initial accuracy, if one specific REF70 chip, will the initial accuracy been fixed after built?

Or it might be changed in every power on cycle?

Thanks

Best regards

Mia 

  • 0
    TI__Expert 5440 points

    Hi Mia,

    The output voltage should be around the same voltage after a power cycle. At 25°C, that number will be within ±0.025% of the specified output voltage.

    Thanks,

    Jackson

  • 0 in reply to Jackson Wightman
    TI__Intellectual 2325 points

    Hi Jackson,

    How we take this into understanding: should be around the same voltage after a power cycle?

    If the range is still +-0.025%, isn't is the same range as the initial accuracy range?

    So we are asking this because customer want to know if a one time initial error calibration will work, or they need to do the calibration at every power-up?

    Thanks

    Best regards

    Mia 

  • 0 in reply to Mia Ma
    TI__Expert 5440 points

    Hi Mia,

    For REF70, you can expect the output voltage to return to the same value within the ±0.025 initial accuracy range at 25°C after a power cycle. 

    Another way of thinking about this: power cycling the device does not have a major effect on the output voltage of REF70.

    For example, today in the lab I powered on REF7025QFKHT with no load at 25°C, and it read 2.499488 V, which is within ±0.025%. After powering it on for about a minute, and then power cycling, the DMM read 2.499488 V again. 

    So, when it comes to calibration, an initial calibration on power up should be fine. Please do keep in mind the effects of output voltage drift due to time (long-term drift) and temperature (temperature drift) when doing calibration. Both of these parameters are specified in the electrical characteristics table in the REF70 datasheet. 

    If there are any other questions please let me know.

    Thanks,

    Jackson

  • 0 in reply to Jackson Wightman
    TI__Intellectual 2325 points

    Hi Jackson,

    Well noted, and thanks

    Regards

    Mia