https://devzone.nordicsemi.com/f/nordic-q-a/70174/rtc-operation-with-super-capI would like to use the RTC in the nRF52833 as a clock-calendar. The device will normally be powered by the USB Vbus but must have power fail protection to insure the integrity of the time. For various reasons I cannot use a battery as for backup so Ien-USTelligent Community 13Thu, 07 Jan 2021 21:09:19 GMThttps://devzone.nordicsemi.com/thread/288043?ContentTypeID=1Thu, 07 Jan 2021 21:09:19 GMT137ad170-7792-4731-bb38-c0d22fbe4515:3e74f00e-5af0-4800-b3a1-7477e376db15hmolesworth<p>Maybe instead of DEC4 connect your circuit directly to VCC, and add a schottky to&nbsp;back-drive VCCH. I have a USB/coin cell design which does this. Instead of using BAV99 schottkys I suggest you switch to Maxim ideal diode MAX40200 to&nbsp;reduce losses. See&nbsp;<a href="https://www.maximintegrated.com/en/products/analog/amplifiers/MAX40200.html">MAX40200</a></p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/288005?ContentTypeID=1Thu, 07 Jan 2021 15:16:16 GMT137ad170-7792-4731-bb38-c0d22fbe4515:f39d2c28-1bee-4752-bf9f-30753d6bdca9JWPtn<p>Okay, thank you for the quick response.&nbsp;&nbsp;</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/287997?ContentTypeID=1Thu, 07 Jan 2021 15:07:09 GMT137ad170-7792-4731-bb38-c0d22fbe4515:e7581f34-530c-41e7-9783-9159ee925c26ketiljo<p>No, that won&#39;t work. The POR circuitry is sensing on the VDD pin and will put the device in reset when VDD becomes too low.&nbsp;</p><div style="clear:both;"></div>