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differential amplifierfor ADC?

Question asked by Ahygoon on Jul 26, 2013
Latest reply on Sep 2, 2013 by Ahygoon



I need help to design the measure chain correctly.

I want to measure load cells signal. My signal is between -4.4mV and 4.4mv. (sensor sensitivity = 0.55mV/V @5t used with 8V supply).

We will use an AD7195.

To have a good measure, we want to use an amplifier before the ADC. But I'm a little confused by the different product: differential, difference or instrumentation amplifier.

For me the important points are:

- low noise : we need precision

- low temperature drift (gain and offset)

- gain will be less than 50 (we will choose later the right PGA factor in the ADC, typically 10) to make the signal range correspond to the ADC input range.


For offset, I think it is less important as we calibrate our system => offset is corrected by the callibration.

Temperature is important as we can work on a large temperature range (-40°C -> 70°C  => -40°F -> 158°F)


So temperature drift is very important.


Can you help me to choose the good product?

Do you have advices or do you see other points to be considered?