Instrumentation Amplifier - Recommendations

Hello Arduino friends!

I am looking for an instrumentation amplifier that will allow me to amplify a rather small voltage signal (a few millivolts) to a range that I can then feed into the Arduino ADC.

I was hoping someone with experience in this might be able to recommend a good IC for this kind of application?

Thanks a lot in advance! Tom

Errr....what are your constraints? Is surface-mount OK or do you want through hole? What is the bandwidth of the signal?

Let's start with the low-cost INA126PA and see if you complain :)

http://focus.ti.com/lit/ds/symlink/ina126.pdf

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Thanks for your reply RuggedCircuits!

SMD is just fine. The signal comes from a Photodiode that is in series with a resistor and thus is a small DC voltage. I haven't made the final decision on the value of the resistor but the signal will probably be between 25mV and 100mV.

Do you need any other information for a funded recommendation? Would the INA126PA still be a good choice here?

Thanks a lot mate, I appreciate your help! Tom

Photodiode? Are you sure you don't want a transimpedance amplifier then?

http://www.jensign.com/transimpedanceamp/index.html

(one of many links) That circuit makes a nice current-to-voltage converter, a bit better than a resistor as a current-to-voltage converter.

If you want to stick with an InAmp...how quickly will your photodiode signal be varying? Are you using it just for light detection? or are you using it for optical communication? (really, this is a question about the bandwidth of the signal)

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With the current design TIA wasn't really possible, but since there were already a few things not perfect with the design, I might just take a step and rethink if I can't change the entire thing.

Thanks for your help though, I might get back to you on that issue ;)

Have a great day! Tom

Good old TL064 will do the job