LR645

LR645 High Input Voltage SMPS Start-up / Linear Regulator Ordering Information Order Number / Package Max. Input Voltage 450V TO-92 LR645N3 TO-243AA* LR645N8 TO-220 SO-8 Die Product marking for TO-243AA: LR6❋ where ❋ = 2-week alpha date code LR645N5 LR645LG LR645ND *Same as SOT-89. Product supplied on 2000 piece carrier tape reels. Features ❏ Accepts inputs from 15V to 450V ❏ Compatible with industry standard PWM ICs. See application note AN-H28. ❏ Output currents up to 3mA continuous, 30mA peak ❏ Supply current typically 50µA ❏ Line regulation typically 0.1mV/V ❏ Output can be trimmed from 8.0V to 12V ❏ Output current can be increased to 150mA with external FET General Description The Supertex LR6 is a high input voltage, low output current linear regulator. It has a 3-terminal fixed output voltage version available in TO-92, TO-220 and SOT-89 packages as well as an adjustable voltage version available in 8 pin SOIC package. The 3-terminal version functions like any other low voltage 3-terminal regulator except it allows the use of much higher input voltages. When used in a SMPS start-up circuit, it eliminates the need for large power resistors. In this application, current is drawn from the high voltage line only during start-up. Only leakage current flows after start-up thereby reducing the continuous power dissipation to a few milliwatts. The adjustable voltage version allows trimming of the output voltage from 8V to 12V. This version can also be connected to an exter...