Best ADC?

Hello,

I've chosen the arduino Due becaus it offers the best ADC resolution (12 bits). However, it doesn't operate in 5V but in 3.3V, is it somehow problematic? Else, I would like to know if there is another Arduino with the same ADC resolution.

In fact, I would like to transmit data from a CO2 sensor through an Ethernet connexion (not to internet, I want to transmit it to a server). But, the Ethernet shield operates with 5V, and the Due with 3.3V. Are they compatible or did a make a huge mistake?

Thanks for your help!

There are plenty of external ADCs available with even 16 bit precision.
If you need more than 10 bits that is the way I would go

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