Battery level less than 3.6V: is a resistor necessary?

RE: Battery level less than 3.6V: is a resistor necessary?

Daniel Reisfeld — Fri, 05 Oct 2018 07:09:57 GMT

Thanks!

RE: Battery level less than 3.6V: is a resistor necessary?

Einar Thorsrud — Fri, 05 Oct 2018 06:56:44 GMT

You can see from the SAADC electrical specification that a acquisition time of 3 µs is sufficient as long as the source resistance is <= 10 kΩ. And that is certainly the case when you measure directly without any resistor.

RE: Battery level less than 3.6V: is a resistor necessary?

Daniel Reisfeld — Thu, 04 Oct 2018 21:04:33 GMT

If there is no resistor?

RE: Battery level less than 3.6V: is a resistor necessary?

Nguyen Hoan Hoang — Thu, 04 Oct 2018 20:52:33 GMT

It is not related to whether you have a resistor or not.

RE: Battery level less than 3.6V: is a resistor necessary?

Daniel Reisfeld — Thu, 04 Oct 2018 20:50:30 GMT

Thanks!

I guess the answer for my second question is indeed 3 micro-seconds - right?

Daniel

RE: Battery level less than 3.6V: is a resistor necessary?

Nguyen Hoan Hoang — Thu, 04 Oct 2018 19:56:16 GMT

If your nrf is directly powered by the battery, you don't even need to connect to the analog pin. Do the acquisition from internal VDD. If nrf is powered by a regulator then you need to add a resistor divider to match the voltage of your VDD.