I'm using the ADS1281 to accurately measure DC potentials. In this application, the ADS1281 has ~1000 ppm of nonlinearity through the range. It is a high-polynomial nonlinearity that cannot be modeled well. The ADS1281 is only being used within half full scale with differnential inputs and differential references. (<+-2.5V)
I have taken simultaneous input potential and output measurements with 20s averaging and have good repeatability. Noise does not appear to be a problem?! The references are high accuracy and look very clean.
the ADS1281 is operating at a stable and continuous 2 kHz data rate and is outputing clean data with no over-ranges. Should I expect a DC linearity approaching 1ppm?
If I use the modulator outputs directly, can I get the linearity I'm looking for?