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I have a voltage output sensor that I'm trying to connect to my STM32 ADC. The datasheet for the sensor states:

Assuming an effective output impedance of 25Ω, the minimum impedance of the measurement system should be 75KΩ.

However, the STM32 datasheet states that the external input impedance (Rain) for the ADC input should not be greater than 300Ω. How do I connect the sensor to the ADC? I was originally thinking putting a 75k resistor in series to the ADC but the STM datasheet has confused me on if that's actually not a good idea.

mhold
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1 Answers1

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How do I connect the sensor to the ADC?

Use an appropriate op-amp buffer circuit. It should have easily an input impedance into the tens of MΩ and, it's output impedance will be a few ohms. But, you do need to know the bandwidth of your signal before you start throwing any old op-amp onto a circuit board.

How to determine what's a suitable op-amp

Andy aka
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