aaron_do wrote on Jul 5th, 2013, 6:32pm:Hi,
Apart from one input being inverting and the other being non-inverting (i'm guessing that's not it), I'm not really sure without looking at how everything is connected up.
How big is the difference. I guess you can make sure that the supply rails are really + and - opposites. Also you could probe vout when both inputs are grounded to make sure it is also ground. Also how small is your input? There is some DC offset between the inputs but according to the datasheet its very small...
Aaron
hi....thanks again for your reply...i have done some check accordingly
ground potdential (both input grounded) : 2~4 mv
the difference ranges from 100 to 200 mv
thats a lot because sensor input is normally very small. the unity gain output is around 29-30 mv.