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ADS1248 Burnout current

Takumi Suzuki1
Mastermind 8610 points
Other Parts Discussed in Thread: ADS1248

Hi,

Could you tell me the "Burnout current : 0.5/2/10uA"  accuracy（error%) of ADS1248?

Thank you,

Best Regards,

  • 0
    TI__Guru* 98235 points
    Takumi-san,


    The accuracy isn't specified, but based on some older characterization data, it is likely about +/-25%. It is not very accurate, and has a large standard deviation. This function is not a precision part of measurement and should only be used to detect an open circuit as if a sensor has burned out.

    Out of curiosity, is there a reason for this question? Does your customer have a particular need for this to be a set of precision current sources.


    Joseph Wu
  • 0 in reply to Joseph Wu
    Mastermind 8610 points

    Joseph-san,

    Thank you for your reply!

    The customer tries to use the current to detect if sensor has burned out.

    They are considering to use it all time, that is to say, the current always flows to the sensor and will cause offset voltage.

    So they need the accuracy..

    Best Regards, 

  • 0 in reply to Takumi Suzuki1
    TI__Guru* 98235 points
    Takumi-san,


    The burnout detection current sources should not be kept on all of the time. The currents do not match well enough (perhaps also 25%) to do this. As you mentioned, the mismatch in current may cause an offset in the ADC measurement.

    If they want to use the burnout current detection, they will need to do a sample measurement. They should stop the normal precision measurement. Turn on the burnout detection current sources. Run a sample measurement, then turn off the burnout detection current sources, and resume precision measurements.


    Joseph Wu
  • 0 in reply to Joseph Wu
    Mastermind 8610 points

    Hi Joseph-san,

    Thank you very much for your adivce!

    I understood well and I will explain this to the customer soon.

    Regards,