The PT4119E is a continuous conduction mode inductive step-down converter, designed for driving single or multiple series connected LED efficiently from a voltage source higher than the total LED chain voltage. The device operates from an input supply between 6V and 50V and provides an externally adjustable output current of up to 1A. The PT4119E includes the power switch and a high-side output current sensing circuit, which uses an external resistor to set the nominal average output current, and a dedicated DIM input accepts either a DC voltage or a wide range of pulsed dimming. Applying a voltage of 0.3V or lower to the DIM pin turns the output off and switches the device into a low current standby state. The PT4119E is available in SOT89-5 package. FEATURES  Simple low parts count  Wide input voltage range: 6V to 50V  High efficiency (up to 97%)  Up to 1A output current  Single pin on/off and brightness control using DC voltage or PWM  Up to 1MHz switching frequency  Typical 3% output current accuracy  Inherent open-circuit LED protection  Inherent Rcs open protection  High-Side Current Sense  Hysteretic Control: No need compensation  Adjustable Constant LED Current  Thermal shutdown APPLICATIONS  Low voltage halogen replacement LEDs  Automotive lighting  Low voltage industrial lighting  LED back-up lighting  Illuminated signs  SELV lighting  LCD TV backlighting