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ADS1216 number of effective bits

Shaul Zuarets
Prodigy 70 points
Other Parts Discussed in Thread: ADS1216

Hi all,

We have the ADS1216 component.

We have a problem, when connecting a battery to our analog input, we read the first 12 bits stable. But the 12 less significant  bits are changing all the time.
I'm trying to find out if the problem is hardware (our board) or the ADS1216 configuration.

In the documentation, the only parameter that influence the accuracy I've found is the decimation ratio. We are using the default settings so the decimation ratio is  1920 (11110000000) so it should be enough. Am i missing something in the configuration? Or I can say for sure it's an hardware problem?

Thanks in advance,

Shaul

  • 0
    TI__Guru* 97775 points

    Shaul,


    Some of the noise may be coming from your setup. There can be problems with power supply noise coupling in to the measurement, and EMI causing extra noise. I would take a series of measurements and plot the data coming out of the ADC to see if there is some periodicity in the measurement (such as 50 or 60Hz noise).

    One thing that is often overlooked is the noise of the reference. If you are comparing the input to the reference, the noise of the reference is reflected in the input measurement. What sort of reference are you using? If it isn't a low noise reference, then this is likely your problem.

    Joseph Wu