According to the NanoESP32 User Manual, the 3.3V jump solder jumper should be cut in order to power the board via its 3.3V pin:
I’ve powered my NanoESP32 on its 3.3V pin using a 3.3V regulated source, without making this cut, and it powered and ran just fine.
I did not connect the NanoESP32 to USB while powered this way.
So - Is this cut required? Or just strongly suggested to provide some form of protection?
Sometimes people get lucky! The designer has several valid reasons for stating this. The board is expected to work in a lot of different applications. If it were me I would cut the jumper, and I am saying this with a lot of design experience.
If you don't cut the jumper, then you are feeding 3.3V on to pins of the unpowered MP2322GQH step down converter.
This is bad practise and could cause the IC to fail.
Thanks. Is this schematic part of some datasheet I can look at?
Is it just to protect the step down converter then? Or also the USB?
Why, were you trying to see if the NanoESP would burn up or not?
It is an excerpt from the official Nano ESP32 schematic at: docs.arduino.cc/resources/schematics/ABX00083-schematics.pdf
Initially I did not realize this solder jumper existed on the board, so I went ahead and powered the Nano through its 3.3V pin without cutting it.
It worked and seems to be powered just fine. But after realizing this solder jumper exists, I’m trying to understand how necessary cutting it is, if I still power it this way.
If the User manual says it is necessary then it must indeed be necessary.
If you want to run the risk of damaging the Nano or other devices then do what you wish.
