Voltage regulator, fixed, 8 ... 12 V, TO-92

LR745 is a high input voltage SMPS start-up circuit. The LR745 is ideally suited for use with industry standard low-voltage PWM ICs having start thresholds of 13.9 to 18.0 V. It allows the PWM ICs to be operated from rectified 120 or 240 V AC lines, and eliminates the use of power resistors often used for this purpose. The internal circuitry of the LR745 allows the PWM ICs to operate at a VCC voltage below their start threshold voltage after start-up. The auxiliary voltage can be less than the start threshold voltage, which allows for improved efficiency. Current from the high-voltage line is drawn only during the start-up period. After start-up, the internal high-voltage line is disconnected from the IC, thereby reducing the continuous power dissipation to a minimum.

- Accepts inputs from 35 - 450 V
- Output current limiting
- For PWM ICs with start-up threshold voltage of 13.9 - 18 V
- Very low power consumption after start-up

Technical data:
- Input voltage: 25 - 450 V
- Output voltage: 13.9 - 18.0 V
- Output current: 2 mA
- Line regulation: 0.0001 (%/V)
- Load regulation: 0.5 (%/mA)