The Power Good (PGOOD) pin is an open drain output. After the FB pin voltage is between 90% and 115% of the internal reference voltage (V_REF) the PGOOD is de-asserted and floats after a 500-µs de-glitch time. TI recommends a pullup resistor of 100 kΩ to pull it up to VCC. The PGOOD pin is pulled low when the FB pin voltage is lower than V_UVP or greater than V_OVP threshold or in an event of thermal shutdown or during the soft-start period.