Damn, you could have fixed this with a lot less hassle and hardware revision by biasing that output comparator properly with a second resistor to GND in additio

Damn, you could have fixed this with a lot less hassle and hardware revision by biasing that output comparator properly with a second resistor to GND in addition to the 3.3V pull-up. Happy to show you what I mean with a quick sch sample if you give me a contact email. My email is the same as my username but at Gmail. Only mention this because: - MMBTs are dirt cheap, - they’re even cheaper when you buy at qty, and your device uses three, whereas you’d only have a single zener and single MMBT otherwise. End of the day, though - your board, your design, your decision.