Hi,
I will use LM3880 for power sequencing of all 3 outputs of TPS65251. I also need to use PGOOD output of TPS65251 to reset my CPU. According to TPS65251 datasheet :
"The PGOOD pin is pulled low when any buck converter is pulled below 85% of the nominal output voltage. The PGOOD is pulled up when all three buck converters’ outputs are more than 90% of its nominal output voltage and reset time of 1 second elapses."
So PGOOD monitors all of 3 outputs. This is what i want but my only concern is that when i enable the first output, could PGOOD become active-high as the other two outputs are currently inactive and thus not needed to be taken into account for PGOOD ? I want PGOOD to remain low as long as all three outputs are at the needed level regardless of situation of their enable pins. Is this the case ?
One more thing, could i connect PGOOD to 3.3V pull-up as it is open-drain output ?
Thanks,
makif
