The SMBJ5.0A-TR trips at 6.0V. It's a TVS not a Zener, and goes full short circuit at that voltage.In fact there's a 5V zener (...from the part number, looks like a TVS) between VBUS and GND, which will suppress any voltage above 5V in any case.
As to the buttons, have you measured the voltage across the pads with the system running? That will show you where it pulls up to.
Statistics: Posted by rpdom — Thu Apr 25, 2024 7:36 am