nRF52840 ADC and GPIO Input Resistance Over Temperature

[EugeneGalust]

Hello,

I have a questions on the ADC and GPIOs front end input resistance over operational temperature range, as our final product operating temperature shall well beyond room temperature.

I went through Nordic’s DevZone forums and infocenter datasheets and could not find the information I am looking for. 

From the datasheets, we know that there’s parasitic input resistance, R_INPUT (could be even lower than the typical value of 1 MOhm @ T_HIGH), present all the time, in parallel with the sampling capacitor.

Could you, please, provide the R_INPUT curves (tabled or graphical representation) over the device’s operating temperature of the most representative set of data (preferably different batches or chips)?

References:

https://devzone.nordicsemi.com/f/nordic-q-a/37680/nrf52840-what-is-the-input-impedance-of-the-adc-inputs-in-spec-it-is-greater-than-1m-but-how-much

https://infocenter.nordicsemi.com/index.jsp?topic=%2Fcom.nordic.infocenter.nrf52832.ps.v1.1%2Fsaadc.html&cp=2_1_0_36_11_0&anchor=unique_1874651084

https://devzone.nordicsemi.com/f/nordic-q-a/44923/more-detailed-specification-of-saadc-input-impedance

https://devzone.nordicsemi.com/nordic/nordic-blog/b/blog/posts/measuring-lithium-battery-voltage-with-nrf51

Best Regards,

Eugene

[JONATHAN LL]

The post from Kenneth here still holds true.


You can assume 0.01uA as a worst case scenario for temperature and voltage. 

If there is some specific certification or similar that you are after then you can create a private ticket and we can try to progress further if this was not enough information.

Regards,
Jonathan