7.3.11 Power Good (PGOOD)

The LM46001 has a built-in power-good flag at the PGOOD pin to indicate whether the output voltage is within its regulation level. The PGOOD signal can be used for start-up sequencing of multiple rails or fault protection. The PGOOD pin is an open-drain output that requires a pull-up resistor to an appropriate DC voltage. Voltage detected by the PGOOD pin must never exceed 12 V. A resistor divider pair can be used to divide the voltage down from a higher potential. A typical range of pullup resistor value is 10 kΩ to 100 kΩ.

When the FB voltage is within the power-good band, +4% above and -4% below the internal reference V_REF typically, the PGOOD switch is turned off and the PGOOD voltage is pulled up to the voltage level defined by the pullup resistor or divider. When the FB voltage is outside of the tolerance band, +10 % above or -10 % below V_REF typically, the PGOOD switch is turned on and the PGOOD pin voltage is pulled low to indicate power bad. Both rising and falling edges of the power-good flag have a built-in 220-µs (typical) deglitch delay.