I am designing a differential sensor that will be placed on the skin to detect biopotentials. Two inputs are fed into an instrumentation amplifier that has a reference set at 1.5 volts (VREF15 in the schematic). That 1.5 voltage reference is also tied to the skin through a "ground" electrode. The 1.5v reference is used as "ground" in order to capture the full signal wave as the sensor is powered by a single battery.
Using the LTC2055 as a buffer, I've found that I'm not getting enough output current to drive my reference. Is the high impedance of the skin the problem (skin is "SigC" in the schematic)? What do I need to do to calculate the necessary output current needed for the opamp?
The short circuit output current of the opamp I'm using is 140 micro amps.