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LM138QML

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SNVSAA9 – OCTOBER 2017

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7.4 Device Functional Modes

7.4.1 Normal Operation

The device OUTPUT pin sources current necessary to make the OUTPUT pin 1.25-V greater than the ADJUST

terminal to provide output regulation.

7.4.2 Operation With Low Input Voltage

drop out and the OUTPUT voltage is then the INPUT voltage minus the drop out voltage.

7.4.3 Operation at Light Loads

The device passes its bias current to the OUTPUT pin. The load or feedback must consume this minimum

current for regulation or the output may be too high. A 250-Ω feedback resistor between OUTPUT and ADJUST

consumes the worst case minimum load current of 5 mA.

7.4.4 Operation in Self Protection

When an overload occurs, the device shuts down the Darlington NPN output stage or reduces the output current

to prevent device damage. The device automatically resets from the overload. The output may be reduced or

alternate between on and off until the overload is removed.