The PGOOD pin is an open-drain output. When the feedback voltage of each buck converter is between 95% (rising) and 105% (falling) of the internal voltage reference, the PGOOD pin pulldown is deasserted and the pin floats. TI recommends using a pullup resistor with a value of 10 kΩ to 100 kΩ connected to a voltage source that is 5.5 V or less. The PGOOD pin is in a defined state when the VIN input voltage is greater than 1 V, but with reduced current sinking capability. The PGOOD pin achieves full current sinking capability after the VIN input voltage is above UVLO threshold, which is 3.8 V.

The PGOOD pin is pulled low when any feedback voltage of buck converter is lower than 92.5% (falling) or greater than 107.5% (rising) of the nominal internal reference voltage. Also, when the PGOOD pin is pulled low and during an UVLO condition on the input voltage, thermal shutdown is asserted, the ENx pin is pulled low, or the converter is in soft-start period.