https://devzone.nordicsemi.com/f/nordic-q-a/16614/3-6v-on-nrf51822-gpio-14ua-sink-current-okI&#39;m attempting to use a GPIO configured as no-pull to determine if a 5V line is connected to the board for charging a battery. I have the 5V line going to a GPIO through a 100k resistor. Bus power to the nRF51822 is 3.3V, and I measure 3.6V at the GPIOen-USTelligent Community 13Wed, 28 Sep 2016 15:25:47 GMThttps://devzone.nordicsemi.com/thread/63551?ContentTypeID=1Wed, 28 Sep 2016 15:25:47 GMT137ad170-7792-4731-bb38-c0d22fbe4515:80460bc7-0697-43d8-a762-8a5c5a14cf6eDylan<p>I agree with you. That is my preferred design, but this has been a discussion with a colleague and I wanted to get some outside opinions on the matter. Thank you for your input.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/63550?ContentTypeID=1Fri, 23 Sep 2016 10:28:20 GMT137ad170-7792-4731-bb38-c0d22fbe4515:e3c50d9e-f8ad-4e7b-b2ce-bcbaef8471c4Ole Bauck<p>If the spec says max VDD+0.3, then don&#39;t go over it. Yes the protection diode will sink the current to VDD, but that doesn&#39;t mean you can do it.</p> <p>Why not use a voltage divider from the 5V source such that 3.3V is seen on the pin whenever the 5V source is there?</p><div style="clear:both;"></div>