nRF52: Gain error temperature coefficient of 0.02%/C assume calibrated?

[nikolrobottesla]

I will be using the nRF52 adc from -20C to 85C and am trying to determine if I need to calibrate and if so how much temperature difference I can have before it is time to calibrate. I am concerned about uAh.

Does the gain error temperature coefficient in the nRF52832 datasheet (0.02%/C) assume the ssadc was recently calibrated?

If not, what is the gain error temperature coefficient when calibrated? If so, what is the gain error temperature coefficient when not calibrated?

Also how long does the calibration take?

[Carsten Wulff]

The offset calibration will only correct the offset over temperature, but it will not affect the gain error.

I've checked from -10C to +70C on one device, and saw a change in offset of -3 LSB10b to 4 LSB10b, that should correspond to 0.0875 LSB10b/C

The calibration time varies with TACQ, and OVERSAMPLE, the ADC needs a certain number of samples to complete calibration, so the best is checking the time from task to event for calibration in your particular setup.