i realize a project with the nano 33IOT. The sketch runs only properly, when the USB - Cable is connected to a PC. If I use the Vin at 7V hogs the processor after a few seconds.
I looked for the failure and I did some measurements at Pin and <3.3V out>. For these test a have used a new nano without any personal programming - right out of the box. I tested 4 devices.
Every device seems to have the same issue. The board voltage oscillating with 1Vpp around the 3.3 V main level. See the attached scopes.
So I used a stable voltage source at 3.3V and connected the board thru the <3.3V out>. All nanos works properly. No crashes.
I think, that the sept down converter MPM 3610 is the problem. These oscillations can’t erased by an 100uF capacitor.
Have anyone any suggestion, what I can do? Have someone the same issue?
I tested the Nano 33 BLE. This board is ok. I tested also the Nano Every. Here I can see horrible oscillations until 1.6Vpp.
What the hell…