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OPAMPEVM-SOT23: How to evaluate the actual accuracy of an ADC?

Lichen114
Prodigy 15 points
Part Number: OPAMPEVM-SOT23
Other Parts Discussed in Thread: ADS131A04

I just have finished the design of  ADS131a04. The general design is as follows:

I can use the dc source(Source Accuracy at  1mv) to evaluate the ADC.  However, due to the signal source accuracy problem, I can't get the actual accuracy of ADC. just sotp at the mv level.

So tell me, what signal source do you use to evaluate ADC?  please give me the  definite  element or equipment.

 What device is used to measure buffer output?   high precision multimeter? or  oscilloscope?

 Is there some  complete test plan?

  • 0
    TI__Expert 6560 points
    Hi Lichen114,

    For a DC source, a calibrated Source-Measure unit could provide the accuracy you're looking for. As an alternative, I know that circuits like the Kelvin-Varley voltage divider can be used to generate fine voltage steps from an external reference, so that could be an option.

    For measurements, a good rule of thumb would be to have equipment that can measure ~10x finer resolution for a thorough characterization. An oscilloscope won't hit this level of performance for a 24-bit ADC, as most oscilloscopes have only 8-12 bit converters (possibly increased to 10-16 bits by oversampling).

    A 6.5-digit multimeter is comparable to a 22-bit converter, and a 7.5-digit multimeter is comparable to a 24-bit converter. An 8.5-digit DMM like the HP/Agilent/Keysight 3458A, would be the best instrument to use for testing out to 24-bit accuracy.