https://devzone.nordicsemi.com/f/nordic-q-a/76544/nrf52840-dk-external-power-supply-onboard-debuggerDear all, For the purposes of the application that I am currently developing, I would like to operate the nRF52840-DK with an external power supply. From the DK&#39;s user guide I have understood that in order to supply the board with exactly 3.3V I coulden-USTelligent Community 13Tue, 22 Jun 2021 11:48:49 GMThttps://devzone.nordicsemi.com/thread/316462?ContentTypeID=1Tue, 22 Jun 2021 11:48:49 GMT137ad170-7792-4731-bb38-c0d22fbe4515:f38f0d05-73e9-405f-8e50-790d4046b83dhaakonsh<p>Hmm, If you cut SB40 and 41 you should be able to power the nRF from&nbsp;P23 at 5V. If you&#39;ve set the&nbsp;<a title="REGOUT0" href="https://infocenter.nordicsemi.com/topic/ps_nrf52840/uicr.html?cp=4_0_0_3_4_0_7#register.REGOUT0">REGOUT0</a>&nbsp;register in UICR to 0x5 (3.3V) the nRF will operate at 3.3V.<br /><br />Then you should be able to run the board from the USB connector as normal. Be warned though that the debugger might not like 3.3V on the pins that interface with the nRF device.&nbsp;</p><div style="clear:both;"></div>