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DAC8775: Solution to improve IOUT accuracy

Zhou Fang67
Expert 4250 points
Part Number: DAC8775
Other Parts Discussed in Thread: TIPD216, TIPD215

Hi,

DAC8775 datasheet shows that IOUT TUE is higher than 0.1% refer to external reference. Is there other way to improve DAC8775 IOUT error to be less than 0.1% refer to absolute 20mA in 0-20mA mode?

Thanks.

Zhou

  • 0
    TI__Mastermind 46290 points
    Zhou,

    Typically high-end AO Modules will implement a two-point calibration scheme at room temperature and/or over temperature to improve accuracy. Between reference initial accuracy, signal chain initial accuracy, and system-wide drift figures this is usually one of the only practical ways, in terms of cost, to maintain <0.1% FSR error over the wide industrial operating temperature range.

    The device actually drifts very well, you can see the TUE specification at room versus that over -40C to 125C only changes by 0.02% FSR. So in most applications a DAC8775 would probably not require a multi-temperature calibration routine.

    The last thing I would point out is that this figure is extremely heavily guard-banded to tester repeatability / capability and is additionally guard banded statistically. The chances of actually seeing a unit that exhibits 0.12% FSR error at room temperature is actually very slim. Most units would more strongly resemble what is shown in the Typical Characteristics Curves or TIPD215 and TIPD216. I realize that isn't the strongest argument against what's published in the datasheet, but it remains true.