I'm using the AD 8220 to amplify a voltage signal from a pressure sensor. The sensor has a very linear response without AD 8220 and a very non-linear response with the amplification as seen on the pictures attached.
What could be the souce of this non-linearity and the variable gain?
I am using the same power supply 5V for the AD8220 and the pressure sensor. The REF and V- pin are connected to the GND. I can not pinpoint the source of this variable GAIN. Does anybody have any ideas?