I've set up the instrumentation amplifier AD8226 as shown in the attached file to measure the current flowing through RLOAD.
Using RG=100R it must achieve a gain of 495 according to table 7 in the datasheet; however I'm obtaining a gain of approximately 6.3 times higher than that (tested with RLOAD=33R, 66R and 150R).
Strangely enough, I've measured the gain to be indeed 495 V/V, introducing 20mV at the input I obtain around 10V at the output. I've tried using RG=1000R with similar results.
Then, why am I not obtaining the expected gain? I cannot measure the voltage drop at the 0R005 resistor because it's too low and I can only see noise with the oscilloscope. Could it be that I'm trying to amplify too weak signals?
Thank you in advance!