Excessive reverse current can damage this device. Reverse current flows through the emitter-base junction 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_O ≤ V_I + 7 V. These conditions are:

• 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, use external protection to protect the device. Reverse current is not limited in the device, so external limiting is required if extended reverse voltage operation is anticipated. Limit reverse current to 5% or less of the rated output current of the device in the event this current cannot be avoided.

Figure 8-3 shows one approach for protecting the device.

Figure 8-2 Example Circuit for Reverse Current Protection Using a Schottky Diode