SBOS848B December 2017 – October 2019 INA381
The ALERT pin is an active-low, open-drain output pulls low when the input conditions are out-of-range. This open-drain output pin is recommended to include a 10-kΩ pullup resistor to the supply voltage. This open-drain pin can be pulled up to a voltage beyond the supply voltage, VS, but must not exceed 5.5 V.
Figure 41 shows the alert output response of the internal comparator. When the output voltage of the amplifier is less than the reference voltage set on CMPREF, the comparator output is in the default high state. When the amplifier output voltage exceeds the reference voltage set at the CMPREF pin, the comparator output becomes active and pulls low. This active low output indicates that the measured signal at the amplifier input has exceeded the programmed threshold level, indicating an overcurrent or out-of-range condition has occurred. See the Alert Modes section for more information about how to set the alert output behavior.