https://devzone.nordicsemi.com/f/nordic-q-a/95201/about-vdd-of-nrf52840Hi, I&#39;m implementing a circuit that uses both ble and usb communication using nRF52840. I&#39;m configuring power source and i&#39;ll configure schematic like reference circuit no.4. I have some question about reference circuit. 1. Is the VDD_nRFen-USTelligent Community 13Wed, 28 Dec 2022 12:46:16 GMThttps://devzone.nordicsemi.com/thread/402437?ContentTypeID=1Wed, 28 Dec 2022 12:46:16 GMT137ad170-7792-4731-bb38-c0d22fbe4515:c3c39e79-8e74-4e4d-aeae-e8cb3608a637Jared<p>Hi,</p> [quote user=""]<p>1. Is the VDD_nRF not an external power source?&nbsp;</p> <p>&nbsp; <span>Are all the VDD_nRF lines in the circuit output from nRF52840?</span></p>[/quote] <p></p> <p>In high voltage mode VDDH is the input for the supply while VDD is an output. VDD is the output of the REG0 regulator and produces VDD_nRF when the VDDH is supplied. All of the VDD nodes should be tied together externally so yes they are outputs. <a href="https://infocenter.nordicsemi.com/topic/ps_nrf52840/power.html?cp=4_0_0_4_2#unique_1706523351">But note that there is a limit of maximum current draw from the VDD node.</a></p> [quote user=""]<p><span>2. I read that VDD level controlled by REGOUT0.</span></p> <p><span>I&#39;ll use VDDH at 3.3V.&nbsp;</span></p> <p><span>Is it ok to set REGOUT0 to 3.3V?</span></p>[/quote] <p>Yes, that&#39;s ok.</p> <p>regards</p> <p>Jared&nbsp;</p><div style="clear:both;"></div>