LR645 High-Input Voltage SMPS, Start-up/Linear Regulator Features Description Accepts inputs from 15 to 450V LR645 is a high-input voltage, low-output current, linear Output currents: up to 3.0mA continuous, 30mA regulator that is available in two versions. A 3-terminal, peak fixed-output voltage version is available in TO-92, TO- Supply current typically 50A 220 and SOT-89 packages, as well as an adjustable voltage version available in an 8-lead SOIC package. Line regulation typically 0.1mV/V Output can be trimmed from 8.0 to 12V The 3-terminal version of LR645 functions like any Output current can be increased to 150mA with other low-voltage, 3-terminal regulator except it allows external FET the use of much higher-input voltages. When used in a Switched-mode Power Supply (SMPS), start-up circuit, Applications LR645 eliminates the need for large power resistors. In this application, current is drawn from the high voltage Off-line SMPS startup circuits (pulse loads) line only during start-up. Only leakage current flows Low power off-line regulators after start-up, thereby reducing the continuous power Regulators for noisy inputs dissipation to a few milliwatts. The adjustable-voltage version allows trimming of the output voltage from 8.0 to 12V. This version can also be connected to an external depletion mode metaloxide semiconductor field-effect transistor (MOSFET) for increased output current. When used in conjunction with depletion mode MOSFET DN2540N5, an output current of up to 150mA is achieved. WARNING The LR645 does NOT provide galvanic isolation. When operated from an AC line, potentially lethal voltages can be present on the IC. Adequate means of protecting the end user from such voltages must be provided by the circuit developer. 2015 Microchip Technology Inc. DS20005384A-page 1LR645 Package Type TRIM NC GATE VOUT NC VIN VOUT GND NC GND +VIN TO-92 8-Lead SOIC GND GND VOUT VOUT GND +VIN VIN GND TO-243AA (SOT-89) TO-220 See Table 2-1 for pin information DS20005384A-page 2 2015 Microchip Technology Inc.