The NMOS pass transistor of the TPS732 provides inherent protection against current flow from the output of the regulator to the input when the gate of the pass transistor is pulled low. To make sure all charge is removed from the gate of the pass transistor, drive the EN pin low before the input voltage is removed. If this process is not done, the pass transistor is potentially left on because of stored charge on the transistor.

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 resulting from the voltage applied on the OUT pin. Additional current flows into the OUT pin from the 80kΩ internal resistor divider to ground (see Figure 6-1 and Figure 6-2).

For the TPS73201, reverse current potentially flows when V_FB is more than 1V above V_IN.