Dear sir,
Based on the ADS1262 datasheet, on page 8, we can get the Noise/4 level of gain error after calibration. it's very good.
But my question is that how to set-up the known-input- voltage to the analog input pin of ADS1262 when do gain calibration, can you tell me the your test signal source equipment name?
Thanks a lot!
Regards,
Jack
Hi Jack,
The typical "Noise/4" gain error specification assumes an ideal full-scale input calibration signal. The factor of "1/4" comes from statistics; the ADC averages 16 conversions, so the level of the noise will be about sqrt(16) or 1/4 the typical RMS noise performance. Obviously, if the calibration signal is inaccurate than the calibration will also provide inaccurate results...
For PGA gain of 1 V/V, you ought to be able to use the reference voltage for the input signal since it will be exactly 100% full-scale. Otherwise, any stable input signal near (under) full-scale could work, so long as it's known (perhaps this voltage is measured back by an HP/Keysight 34401A multi-meter). Otherwise, if the calibration is taking place in the field, you'll have to rely on the accuracy of your on-board reference source.
Note: You can account for a signal smaller than full-scale, when performing gain calibrations, by using the method I described here: 
Best Regards,
Chris
