This post is older than 2 years and might not be relevant anymore
More Info: Consider searching for newer posts

nRF52840 Circuit configuration no.5 VDD voltage addition of 1.6v

When I use circuit configuration no.5, VDD connected to VDDH and have 5V going into VBUS, I see a 1.6V output from the VDD_nRF (VDD/VDDH). 

Normally when I connect a battery (with LDO to supply 3.0V) to the VDD/VDDH everything works fine. However, if I connect USB power directly to the VBUS and remove the battery, I see a 1.6V at the VDD/VDDH. 

This results in the voltage at VDD_nRF at 4.6V another strange thing as it shouldn't add up. 

My USB goes to the VBUS directly and goes to an LDO which then output goes tot he VDD_nRF.

Thank you 

Related