I'm using AD620 to drive a cable of 50 meters. The input + of AD620 comes from the output from a sensor of around 2.5 Volt, Input - is tied to 2.5VDC. ,. Vref is = 0V.
So if the input of the sensor goes below 2.5 then Ad620 is expected to give minus output, and vice versa.
R gain is set to 14 KOhms (gain = around 4 ) . Vs = +/- 12V.
It worked fine, until recently we got 1223 date code and it started to give oscillated output of around 300Khz.
Any help or suggestion on the problem ?