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Associate II
September 3, 2025
Solved

1. Use multiple Op-Amps as differential amplifiers? 2. Do Op-Amps give full 0-3.3V output range?

  • September 3, 2025
  • 2 replies
  • 286 views

Hello,
I had two related questions to clarify - 

1. Can multiple Op-Amps be used in the differential mode simultaneously and their output fed to ADC for measuring input DC voltage?

2. Also, since the Op-Amps inside the STM32G4 MCU are not rail-to-rail, they only output 0-3.3V for the given input. I am only interested in measuring DC input. Connecting the Op-Amp GND to system ground (0V) would give me the full range of output for DC (NOT 1.65-3.3V, but 0-3.3V), right? 

Thanks.

Best answer by Andrew Neil

I guess this is a follow-on from your previous thread ?

It'd be helpful to provide a link there so that people can find the follow-on questions.

 

Have you studied the Op-Amp section in the Reference Manual for the particular STM32G4 MCU you are using?

That will show you all the available options ...

 

You'll find the Reference Manual on the 'Documentation' tab of the Product Page for the particular STM32G4 MCU you are using; eg,

https://www.st.com/en/microcontrollers-microprocessors/stm32g484qe.html#documentation

 

2 replies

Andrew Neil
Andrew NeilBest answer
Super User
September 3, 2025

I guess this is a follow-on from your previous thread ?

It'd be helpful to provide a link there so that people can find the follow-on questions.

 

Have you studied the Op-Amp section in the Reference Manual for the particular STM32G4 MCU you are using?

That will show you all the available options ...

 

You'll find the Reference Manual on the 'Documentation' tab of the Product Page for the particular STM32G4 MCU you are using; eg,

https://www.st.com/en/microcontrollers-microprocessors/stm32g484qe.html#documentation

 

A complex system that works is invariably found to have evolved from a simple system that worked.A complex system designed from scratch never works and cannot be patched up to make it work.
MasterT
Lead II
September 3, 2025

In short, there is no build-in configuration for diif-amp. But you can combine two opa over external wiring, and biasing non-inverting input, Check this thread