USB dual powerhttps://devzone.nordicsemi.com/f/nordic-q-a/41102/usb-dual-powerWe have the device, where 2 power supplys can be applied. One of them is external regulator with 3.3 V output. We used it for additional load in our device. Another one is a 5V from USB - we want to use nRF52840 as peripheral device to conrol externalen-USTelligent Community 13Mon, 03 Dec 2018 15:55:00 GMTRE: USB dual powerhttps://devzone.nordicsemi.com/thread/160049?ContentTypeID=1Mon, 03 Dec 2018 15:55:00 GMT137ad170-7792-4731-bb38-c0d22fbe4515:3b0abeef-24a4-4a6e-a16a-929bd9702c4ahaakonsh<p>In your case you do not need to use&nbsp; REG0 (VDDH) at all. See Reference circuit&nbsp;<a title="Circuit configuration number 5 for QIAA aQFN73, showing the schematic and the bill of materials table." href="https://www.nordicsemi.com/en/DocLib/Content/Product_Spec/nRF52840/latest/ref_circuitry?1071#unique_9885097">Config. 5</a>. In you application you connect&nbsp;USB 5V to VBUS, and External 3.3V to VDD_nrf.</p><div style="clear:both;"></div>