I am currently building a circuit that takes in a ~10uV signal ranging from 1-20Hz. I am using an INA126P for the initial stage of amplification, and amplify the rest through a few stages of non-inverting op-amps. However, when I build the circuit I am getting a negative dc offset out of the instrumental amplifier of around -300mV. The gain for the INA126P is set using a resistor and is currently set to only 100v/v. An attached photo of the ltSpice model can be seen below. Am I making a mistake or is it possibly a faulty amplifier? I was also looking into solutions to fix this: could I use an AC coupling capacitor and is it possible to not effect my 1-20Hz signal input range? Any help is appreciated!
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