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Let's assume I use an OPA1632 differential amplifier and I need to connect its output to a microcontroller (in this case: stm32f407 or stm32f429i). If I'm not mistaken, I would need an ADC with differential input on the microcontroller, right? In the two microcontroller datasheets (407 and 429) I can't find anywhere a reference to a differential ADC.. so I assume these two boards don't have it? Right? Or did I misread the datasheet?

Forgive my ignorance, but could I connect the first output terminal of the OP1632 to the ADC1 pin and the second output terminal to another ADC2 pin? Then, via software, I make the difference... right? I may have said something stupid... but it's the first time I've worked with ADCs.

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  • \$\begingroup\$ Could you link to spec sheets/reference manuals so it is easier to help? \$\endgroup\$
    – L Selter
    Commented Oct 25, 2023 at 10:14

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Looking at STM32F405 RM it does not look like this device has a differential mode.

When compared to a higher end model STM32H7 this clearly mentions a differential mode. You are correct you could just subtract two ADC channels in software to create a differential mode.

This question is discussed in several places easily found with a search engine of your choice:

ST Forum

Reddit

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  • \$\begingroup\$ Thinking about it a little, I don't think the 2 ADC ports work exactly at the same time! So maybe I could have problems with this "coarse" solution of mine and therefore produce an untrue result from the ADC. Thanks anyway for your reply \$\endgroup\$
    – KaleM
    Commented Oct 26, 2023 at 9:56
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    \$\begingroup\$ If your device has 2 ADCs they can be triggered at the same time to get a better result, but unless you are interested in really high frequency signals you could just average out a few samples \$\endgroup\$
    – L Selter
    Commented Oct 30, 2023 at 6:02

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