https://devzone.nordicsemi.com/f/nordic-q-a/34067/nrf52840-powering-itself-from-p-02Hello, We have a custom boards that powers a NRF52840 module from a 1.8v voltage regulator coming from a 3.6v battery. We also connected the positive pole of the battery to the P02 (AN0) pin with the intention of using the 1/6 gain mode and the internalen-USTelligent Community 13Mon, 07 May 2018 06:50:57 GMThttps://devzone.nordicsemi.com/thread/131120?ContentTypeID=1Mon, 07 May 2018 06:50:57 GMT137ad170-7792-4731-bb38-c0d22fbe4515:c3ca8e2e-d22c-47d2-b281-76aec7ef86c1ketiljo<p>Maximum voltage on any pin is VDD + 0.3 V. If you exceed this, the ESD protection diode will start to conduct and you will power VDD via the GPIO.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/131056?ContentTypeID=1Fri, 04 May 2018 16:36:48 GMT137ad170-7792-4731-bb38-c0d22fbe4515:db16cfc1-5477-4a39-807f-c67fd07fb5ddhmolesworth<p>You have a classic phantom power issue, have a look towards the end of this&nbsp;<a href="https://devzone.nordicsemi.com/f/nordic-q-a/32798/nrf52832-io-problem">post</a>&nbsp;which provides a description of what is happening. In some ways you might find a better solution is to throw out the 1.8 volt regulator and instead rely on the 1.3 volt internal switcher; the downside is that other devices on the 1.8 volt rail might consume too much power at some higher value but I observed an overall reduction in power on a design I recently completed. The up side is that now you can measure the battery voltage internally without using an external pin and voltage dividers or FET switches</p><div style="clear:both;"></div>