8.1.4 Reverse Current

Excessive reverse current can damage this device. 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 outlined in this section, all of which can exceed the absolute maximum rating of V_OUT ≤ V_IN + 0.3 V.

• If the device has a large C_OUT and the input supply collapses with little or no load current
• The output is biased when the input supply is not established
• The output is biased above the input supply

If reverse current flow is expected in the application, external protection is recommended to protect the device. Reverse current is not limited in the device, so external limiting is required if extended reverse voltage operation is anticipated.

Figure 37 shows one approach for protecting the device.

Figure 37. Example Circuit for Reverse Current Protection Using a Schottky Diode

Figure 38 shows another, more commonly used, approach in high input voltage applications.

Figure 38. Reverse Current Prevention Using A Diode Before the LDO