Can we do adc reading from the external Li-Po 3.7V battery?

[Jaehong Park]

About 3.7V Li-Po battery on spec., can we read adc value from the battery using p0.04(A1) without external voltage divider circuits?
In fact, 3.7V battery outputs 4V ,seeing after checking the volatage of the battery using multi-meter.

In nRF52832 PS doc, analogue input ranges from ??V value to VDD(3.6V ??).
Then can we read the adc value from the battery directly without the external voltage divider circuit?

[run_ar]

Hi,

Unfortunately you cannot do that. I.e. the product specification says: "The AIN0-AIN7 inputs cannot exceed VDD, or be lower than VSS". See Reference.

[Jaehong Park]

I found the absolute maximum ratings are as followings: https://infocenter.nordicsemi.com/index.jsp?topic=%2Fcom.nordic.infocenter.nrf52832.ps.v1.1%2Fabs_max_ratings.html&anchor=abs_max_ratings.

So, I think the the voltage of external 3.7V battery would be allowed via analog input because the voltage ranges from GND to VDD(maximum 3.9V).

I'd like to be confirmed from you about reading the adc reading directly from external battery.

[run_ar]

Hi,

You need to use a voltage divider. e.g. https://devzone.nordicsemi.com/nordic/nordic-blog/b/blog/posts/measuring-lithium-battery-voltage-with-nrf52