https://devzone.nordicsemi.com/f/nordic-q-a/32613/ok-to-drive-1-8-v-vdd-to-3-0-vThe default value of UICR REGOUT0 is 1.8 V. When in this mode, is it OK to temporarily overdrive VDD to 3.0 V in order to reprogram REGOUT0 to 3.0 V?en-USTelligent Community 13Thu, 22 Mar 2018 08:47:26 GMThttps://devzone.nordicsemi.com/thread/125466?ContentTypeID=1Thu, 22 Mar 2018 08:47:26 GMT137ad170-7792-4731-bb38-c0d22fbe4515:6d25f461-f00d-4e1f-a5c4-d8f7a43a96e0haakonsh<p>Hey Bruce,</p> <p>I do not understand what you are trying to accomplish.</p> <ol> <li>What voltage are you supplying VDDH with?</li> <li>What do you mean by &quot;overdrive VDD&quot;, do you have a separate power supply that feeds into VDD in addition to REG0?&nbsp;</li> </ol> <p>&nbsp;</p> <p>There is a limit on the rise time of VDD. From the datasheet:</p> <p>&quot;A step increase in supply voltage of 300 mV or more, with rise time of 300 ms or less, within the valid supply range, may result in a system reset.&quot;&nbsp;</p> <p>Cheers,</p> <p>Håkon.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/125412?ContentTypeID=1Wed, 21 Mar 2018 16:50:11 GMT137ad170-7792-4731-bb38-c0d22fbe4515:dc6e73ba-0e2f-412f-8364-a95c14ddee40owl-wy7n<p>I note that it seems to work OK.&nbsp; I just want to know if there is any reason not to do this.</p><div style="clear:both;"></div>