LR12 is a high voltage, low output current, adjustable linear regulator. It has a wide operating input voltage range of 13.2 - 100V. The output voltage can be adjusted from 1.20 - 88V, provided that the input voltage is at least 12V greater than the output voltage. The output voltage can be adjusted by means of two external resistors R1 and R2 as shown in the typical application circuits. The LR12 regulates the voltage difference between VOUT and ADJ pins to a nominal value of 1.20V. The 1.20V is amplified by the external resistor ratio R1 and R2. An internal constant bias current of typically 10µA is connected to the ADJ pin. This increases VOUT by a constant voltage of 10µA times R2.

The LR12 has current limiting and temperature limiting. The output current limit is 100mA maximum and the minimum temperature limit is 125°C. An output short circuit current will therefore be limited to 100mA maximum. When the junction temperature reaches its temperature limit, the output current and/or output voltage will decrease to keep the junction temperature from exceeding its temperature limit. For SMPS start-up circuit applications, the LR12 turns off when an external voltage greater than the output voltage of the LR12 is applied to VOUT of the LR12. To maintain stability, a bypass capacitor of 100nF or larger and a minimum DC output current of 500µA are required.