The INA185-Q1 allows linear current sensing operation with the output close to the supply rail and GND. The maximum specified output swing to the positive rail is 25mV, and the maximum specified output swing to GND is only 3.5mV. To compare the output swing of the INA185-Q1 to an equivalent operational amplifier (op amp), the inputs are overdriven to approximate the open-loop condition specified in many operational amplifier data sheets. The current-sense amplifier is a closed-loop system, therefore the output swing to GND can be limited by the offset voltage and amplifier gain during unidirectional operation (V_REF = 0V) when there is zero current flowing through the sense resistor. To define the maximum output voltage under the zero current condition, the INA185-Q1 Electrical Characteristics table specifies a maximum output voltage of 6mV for the A1 device, and 12mV for all other devices.