nRF52832 ADC precision

[florentb]

Hello, I have two questions regarding nRF52832 ADC, which are not documented :

• what is the precision / tolerance of the internal 0.6V reference?

• what is the tolerance of the internal resistance ladder? Can it be used for precision measurements, as a low-side resistor divider?

Thanks, Florent

[Carsten Wulff]

The internal reference impacts the gain error of the ADC, and the gain error is reported in the PS. The gain error includes the precision of the internal reference.

The variation of the absolute value of the internal resistor is quite large, usually in the 10% to 20% range. The relative accuracy betweeen the two resistors is very good, usually in the 0.1% to 1% range.

[Andrea Gangemi (Flex)]

Hi,

You mention that relative accuracy is between 0.1% and 1% How this relative accuracy change in funtion of temperature?

Thanks, Andrea

[Carsten Wulff]

The temperature dependence depends on layout, but I would expect the relative accuracy to change little with temperature for the resistors. They are very close to each other, and will experience the same temperature, thus the relative change should be small.