ADC Voltage reference doubt

[Sergi Hernandez]

Posted on November 30, 2017 at 13:54

Hi, 

I'm working with a STM32L053R8 and I want to use some ADC pins. I have a doubt about the input voltage range. 

Does the ADC have an independent power supply? 

Which is the input voltage range of the ADC?

For example:

Let's suppose that I am supplying the STM with 3.3 V, and I am using 12 bits from the ADC.

That means that...?

- The input voltage range goes from 0V to 3.3V?

- The step-quantization is 3.3/(2^12-1)?

Thanks!

🙂

 #hal #adc #stm32 #stm32l0 #voltage-reference #voltage-range #adc-supply

[waclawek.jan]

Posted on November 30, 2017 at 15:07

Does the ADC have an independent power supply? 

Together with other analog circuits (e.g. DAC), VDDA/VSSA, which is by datasheet required to be connected to the 'digital' VDD/VSS (often through a small inductor in role of a filter).

Which is the input voltage range of the ADC?

VREF- to VREF+. On small packages, VREF- is internally connected to VSSA and VREF+ to VDDA.

Let's suppose that I am supplying the STM with 3.3 V, and I am using 12 bits from the ADC.

That means that...?

- The input voltage range goes from 0V to 3.3V?

- The step-quantization is 3.3/(2^12-1)?

Yes, unless - as said above - you have separate VREF different from VDDA.

JW