VDD to voltage supply in high voltage mode

[anromanof]

Hi,

I was wondering if there are any problems with connecting VDD to an external power supply when using nrf52840 in the high voltage mode?

I would like to connect VDDH to external +5V and also connect VDD to external +1V8 (I would also use the default VDD of +1V8 in REGOUT0). The reason I want to do that is because I don't want to create an extra power plane in my design as I already have regulated +1V8 for other components. As far as I understand, because +1V8 is the default value of VDD in REGOUT0, even during reset, VDD will stay at +1V8, which will not introduce the voltage level conflict to my external +1V8 line.

Thanks

[Marjeris Romero]

Hi

This doesn't seem like a good idea, high voltage mode is entered when the supply voltage is only connected to VDDH pin and the VDD pin is not connected to any voltage supply.

If you don't need an extra 1V8 rail you can keep VDD disconnected.

Best regards,

Marjeris