IS31LT3353

IS31LT3353 40V/1A BUCK LED DRIVER WITH INTERNAL SWITCH October 2014 GENERAL DESCRIPTION The IS31LT3353 is a continuous mode inductive step-down converter, designed for driving a single LED or multiple series connected LEDs efficiently from a voltage source higher than the LED voltage. The chip operates from an input supply between 6V and 40V and provides an externally adjustable output current of up to 1A. The IS31LT3353 includes an integrated output switch and a high-side output current sensing circuit, which uses an external resistor to set the nominal average output current. The output current can be dynamically adjusted by adding either a digital PWM or analog voltage level signal to the ADJ pin. A PWM signal will provide a gated output current while a voltage signal will generate a continuously linear output current. Applying a voltage less than 0.2V to the ADJ pin turns the output off and switches the chip into a low current standby state. The chip is assembled in SOT23-5 package. It operates from 6V to 40V over the temperature range of -40°C to +125°C. FEATURES  Up to 1A output current  High efficiency (up to 97% )  Wide input voltage range: 6V to 40V  Internal 40V power switch  Simple low parts count  Typical 3% output current accuracy  Single pin on/off and brightness control using DC voltage or PWM  Up to 1MHz switching frequency  Inherent LED open-circuit/short-circuit protection  Thermal shutdown protection circuitry  Up to 1200: 1 dimming rate APPLI...