I have looked at many questions with similar titles but cone cover my query.
Question: How can I protect an STM32 Cortex M4 series ADC input when measuring the AUX output voltage from typical smartphones (eg Samsung Galaxy)
Here is a circuit I used to sample the mobile audio output through AUX jack, the measurement will be done by an ADC with maximum voltage input of 3V3 (may be 3.6V but I keep it lower.)
The ADC is part of an STM32F446re microcontroller.
I am advised that this circuit can damage the ADC.
I (and many others) am looking for a safe way (safety is more important than quality of the signal) to sample audio from AUX jack (headphone output/line out/etc) where the solution is independent of the phone and is standard to most of them.