SBVS067R January 2006 – December 2019 TPS737
The NMOS pass element of the TPS737xx provides inherent protection against current flow from the output of the regulator to the input when the gate of the pass device is pulled low. To ensure that all charge is removed from the gate of the pass element, the EN pin must be driven low before the input voltage is removed. If the EN pin is not driven low, the pass element may be left on because of stored charge on the gate.
After the EN pin is driven low, no bias voltage is needed on any pin for reverse current blocking. Reverse current is specified as the current flowing out of the IN pin because of voltage applied on the OUT pin. There is additional current flowing into the OUT pin as a result of the 80-kΩ internal resistor divider to ground (see Figure 29 and Figure 30).
For the TPS73701, reverse current may flow when VFB is more than 1.0 V above VIN.