STM32F030R8 Nucleo-64 Board ADC Voltage Reference

[EFons]

I want to decrease the reference voltage of the ADC to have a better resolution, is it possible to do it?

Could someone explain me how can I do this? I am using the Nucleo-64 board STM32F030R8 and CubeMX to generate the code. Do I have to configure something in the programming code or I just need to provide the correspondent voltage to the right pin of the board?

[S.Ma]

You will need a package which will allow you to access the analog supply pin and connect it to specific regulator.

The voltage chosen can be lower than the digital supply as long as it complies with the electrical parameter, including power up/down scheme.

However, even if you could reduce by 50% the voltage, it would make a 1 bit gain at most.

Averaging multiple sample when possible may give similar results. (doubling the sampling number for an extra bit if white noise as rule of thumb)

[EFons]

I didn't understand, what this package is?

I would try to decrease the reference voltage from 3.3V to 1.5V. I also didn't understand the 1 bit gain part.

I need to measure voltages around 1mV to 10mV but with a better resolution to be more certain.

For example if I am measuring 2.4mV with 12-bit resolution and 3.3V supply this would be around 3 (decimal) to the ADC. If then I measure 4.5mV with the same conditions this would be 6. So, the difference is not that significant, I think.

For 1.5V supply: 2.4mV would be 7 and 4.5mV would be 12, which is a little better.

[S.Ma]

Use an op-amp to magnify the signal amplitude to 3.3V, you will get much more steps from the ADC.

If the op-amp gain is x100 you will get 0.1 to 1V through the ADC at 3.3V which would be lots of steps

And this is how oscilloscopes work isn't it?

[EFons]

That's what I ended up doing, and it worked. But I would like to know, just to be sure, it's possible to do what I wanted?