Could you explain what is it? And can I compensate it?#
I think a reasonable explanation is the choosed gain has effect on the error. The main reason is there are two stages amplifiers to realize up to 128x gain.
Anyway, if you use a fixed gain in your application, you needn't to consider this effect. If you use different again and the matched gain error exceed your requirement, a suggest method is to calibrate the ADC in different gain and reserve the parameter. Using the parameter to compensate your ADC data based on the gain.
PGA Gain Mismatch Error means the error between different gain. For example, input 20mv signal, the error can be explained as the error between PGA = 16 and PGA = 32.
Yes, you can calibrate the error with different Gain value.
How I understand your example, I generate 20 mV, measure by ADUC with PGA16, after measure with PGA32. Difference between results of measuring devided by reference voltage is PGA Gain Mismatch Error. According to datasheet this value should be less than 0.15% FS (1.8 mV with internal reference). Is it right?
Almost right. But please note that here the 0.15% is typical value. And in the case with 20mV input, the full scale with Gain = 16 is +/-62.5mV(125mV).
So system calibration with different gain is strong recommended.
So max absolute value (in mV) of error depends from choosed gain?
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