The output of the PWRGD pin is an open-drain MOSFET. The output goes low when the VSENSE voltage enters the fault condition by falling below 91% or rising above 109% of the nominal internal reference voltage. There is a 2% hysteresis on the threshold voltage, so when the VSENSE voltage rises to the good condition above 93% or falls below 107% of the internal voltage reference, the PWRGD output MOSFET turns off. TI recommends using a pullup resistor between the values of 1 kΩ and 100 kΩ to a voltage source that is 6 V or less. PWRGD is in a valid state once the VIN input voltage is greater than 1.1 V.