Hi, I have a design, where I am trying to measure voltages with a LPC54016. One ADC input is a voltage, that will be on an ADC pin, before the MCU gets powered.
I have VCC_5V that gets converted into VCC_3V3 with a step down DCDC converter. I have 5V going to an ADC input (with a voltage divider, so it is 2.25V at the pin). That means, that the 2.25V will be on the ADC pin before 3.3V at the power supply pins.