Because the reference pin is functionally no different than a second positive input, it can be used with gain simply by leaving it unconnected to the feedback network. This configuration can be very useful in certain cases, such as in DC removal servo loops. In DC removal circuits using traditional in-amps, either the inputs are AC coupled and CMRR and input impedance are reduced, or AC coupling is done after the in-amp, and the gain must be limited so that the DC offset times gain is within the amplifier output range. For a gain of 100, the maximum offset would be one one-hundredth of the supply voltage in these traditional circuits. A servo loop is shown below that has a gain of 101 and a maximum offset tolerance of plus or minus 1 volt with high CMRR and input impedance. This feature set can be very useful in systems that must account for large DC offsets, such as the electrocardiogram or electromagnetic flow-metering systems. This circuit requires careful attention to the input range, which also includes FB, REF, and the differential voltage limit.