SNVS276I April 2004 – February 2019 LM2743
PRODUCTION DATA.
The open drain output on the Power Good pin needs a pull-up resistor to a low voltage source. The pull-up resistor should be chosen so that the current going into the Power Good pin is less than 1 mA. A 100-kΩ resistor is recommended for most applications.
The Power Good signal is an OR-gated flag which takes into account both output over-voltage and under-voltage conditions. If the feedback pin (FB) voltage is 18% above its nominal value (118% x VFB = 0.708V) or falls 28% below that value (72 %x VFB = 0.42V) the Power Good flag goes low. The Power Good flag can be used to signal other circuits that the output voltage has fallen out of regulation, however the switching of the LM2743 continues regardless of the state of the Power Good signal. The Power Good flag will return to logic high whenever the feedback pin voltage is between 72% and 118% of 0.6V.