The INAx191 features an active-high ENABLE pin(s) that shuts down the device when pulled to ground. When the device is shut down, the quiescent current is reduced to 10 nA per channel (typical), the input bias currents are further reduced, and the disabled output goes to a high-impedance state. When disabled, the low quiescent and input currents extend the battery lifetime when the current measurement is not needed. When the ENABLE pin is driven above the enable threshold voltage, the device turns back on. When enabled, the typical output settling time is 130 µs.
The output of the INAx191 goes to a high-impedance state when disabled; therefore, it is possible to connect multiple outputs of the INAx191 together to a single ADC or measurement device, as shown in Figure 7-7. When connected in this way, enable only one INAx191 at a time, and make sure both devices have the same supply voltage. Using the INA2191 with the same approach as shown in Figure 7-7 provides the capability to monitor two currents with a single device.