https://devzone.nordicsemi.com/f/nordic-q-a/31014/nrf52840-high-voltage-mode---inductor-requirementsWe are designing the nrf52840 with high voltage mode and both DCDC regulators. Where can I find the requirements for the external circuitry, like the inductors. For now I only see the reference circuitry no. 4 but I don&#39;t know how strict the requirementsen-USTelligent Community 13Mon, 05 Mar 2018 13:52:31 GMThttps://devzone.nordicsemi.com/thread/122838?ContentTypeID=1Mon, 05 Mar 2018 13:52:31 GMT137ad170-7792-4731-bb38-c0d22fbe4515:ae379bca-6207-4c29-805c-0f9f0dc15f28Florian Zierer<p>Thanks for the check with the designer and for the whitepaper.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/122830?ContentTypeID=1Mon, 05 Mar 2018 13:26:30 GMT137ad170-7792-4731-bb38-c0d22fbe4515:a0ee497e-9001-431e-bf62-8358cc107306ketiljo<p>I checked with the designer, 20 % is ok, there should be no issues with stability.</p> <p>You should consider adding a 100 nF cap in parallel with the 1µF cap in case it&#39;s low. Also see this whitepaper: <a href="http://infocenter.nordicsemi.com/pdf/nwp_030.pdf">nWP-030</a></p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/122612?ContentTypeID=1Fri, 02 Mar 2018 13:17:38 GMT137ad170-7792-4731-bb38-c0d22fbe4515:c7a6ba26-9ec9-427a-86ba-0ec687ef5058Florian Zierer<p>Ok, but when you say you are recommending 10% would 20% also work but not as efficient? Perhaps this is ok for us but if it not working at all that would be bad.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/122585?ContentTypeID=1Fri, 02 Mar 2018 10:09:23 GMT137ad170-7792-4731-bb38-c0d22fbe4515:f5384656-6a46-4587-a1f1-2d467f96baceketiljo<p>Using a 20% inductor for the high voltage DCDC converter may affect the efficiency, so we recommend using 10% here. You can use several inductors in series, no problem.</p><div style="clear:both;"></div>