Q:

Engineer is using the TPS62054 is his design and noted contradicting statements concerning the operation of PG.  On page 13 of the datasheet, stated PG is open drain and can sink 1mA, and to to leave the pin unconnected, or to GND if not used.  Then says "PG pin becomes active HIGH . . " and this is not possible.   The pin is open-drain, driven by a FET to GND, there is no path to Vcc to drive the pin HIGH.  If there was, and the pin was connected to GND as recommended, a short Vcc-GND would be created.  Page 5 says to use a pull-up resistor, but no mention of this on page 13.

In the EVM Section 2.3 says to use a pull-up, and leave unconnected if not used; no mention of connection to GND as in the datasheet.


A:

The PG is an open-drain output that requires a pull-up resistor.  As such, it can be floated or connected toGND if not used. 

With the naming convention 'PG', it indicates a PG (power good) when it is high.  If it were /PG, it would indicate a PG when it were low.  So, the PG pin indicates a power good when it is high. 

Of course, to register a high, it must be connected to a pull-up resistor.  It does not actively pull high, but floats high.