I'm building a device using STM32F0 MCU.
The whole unit is powered with +24V DC delivered via pretty long cables.
This voltage is passed to the DCDC converter, based on RT8259:
In the next step 5V is lowered to 3.3V with simple linear regulator (AMS1117-3.3):
This voltage is used to power the MCU (with additional tantalum 4.7uF and ceramic 100nF per pin).
However the microcontroller has a dedicated "VDDA" pin, which according to datasheet is used as input for PLL, ADC etc.
- Is it required to add additional filter for VDDA?
- Is LC (10uH + 4.7uF) enough?
- If the filter is not present, what would happen? Loss of ADC accuracy (how much?) Loss of clock stability?