8.1.6 Reverse Current

Excessive reverse current can damage the TPS7A78. Reverse current flows through the intrinsic body diode of the pass-transistor instead of the normal conducting channel. At high magnitudes, this current flow degrades the long-term reliability of the device.

Conditions where reverse current can occur are:

• If the device has a large C_{LDO_OUT} and the input supply collapses with little or no load current
• The LDO_OUT pin is biased when the input supply is not present
• The LDO_OUT pin is biased above the voltage of the LDO_IN pin

If reverse current flow is expected in the application, external protection is recommended to provide protect. Reverse current is not limited within the device, so external limiting is required, as illustrated in Figure 30 and Figure 31, if extended reverse-voltage operation is anticipated.

Figure 30. Example Circuit for Reverse Current Protection Using a Schottky Diode

Figure 31. Example Circuit for Reverse Current Protection Using a P-Channel FET