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ADS1230: ADS1230 :what exactly does offset calibration.

Kevin Legendre
Prodigy 20 points
Part Number: ADS1230

Hi everyone,

I'm not sure to well understand what does the offset calibration on the ADS1230.

I see two solutions:

1) the ADS1230 creates an internal short to have an input voltage of 0mv and take a measurement. The result should be 0 so if it's not it saves the value as an offset

2) the offset calibration is used to setup a new 0. Let's say the gain is +-19.5mv at 9.75mv I have an output value of 262144. If I run an offset calibration the adc will define and the new value for an input voltage of 9.75mV will be 0?

 

I'm pretty sur the answer is the first solution, but I would like to be sure.

My application can run during long period and the temperature is not constant. Is it a good solution to periodically run an offset calibration? The offset calibration is it enough to compensate the temperature drift?

Thnk you in advance

 

  • 0
    TI__Guru** 113765 points
    Hi Kevin,

    Welcome to the E2E forum! The offset calibration provides an internal short to mid-AVDD supply. As you stated in option 1, the result should be 0, however you will not ever see exactly 0 due to noise. So depending on the SPEED and GAIN pin selection you will see some variation with respect to applying an external short. As stated in note 1 under the Electrical Characteristics table on page 3, "Offset calibration can minimize these errors to the level of noise at any temperature."

    Option 2 is not available for the ADS1230. This is typically offered with devices that have system calibration options.

    If your system changes temperature, then it is best to issue a periodic offset calibration which will compensate for the ADS1230 offset temperature drift. However, any external component or system drift will not be compensated.

    Best regards,
    Bob B
  • 0 in reply to Bob Benjamin
    Prodigy 20 points
    Thanks a lot Bob for your explanation.
    I’ll make some test with a periodic offset calibration.
    Regards.
    Kevin