IS31LT3353-SDLS4-TR

IS31LT3353 40V/1A BUCK LED DRIVER WITH INTERNAL SWITCH May 2015 GENERAL DESCRIPTION FEATURES 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 and SOT89-5 packages. It operates from 6V to 40V over the temperature range of -40°C to +125°C.     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 APPLICATIONS       LED MR16, MR11 spot light LED street light PAR light Industrial lighting Refrigeration lights Other LED lighting TYPICAL APPLICATION CIRCUIT Figure 1 Typical Application Circuit Note: The capacitor, C2, can’t be removed. And it should be placed as close as possible to the VIN and GND pins, otherwise the operation might be abnormal. Lumissil Microsystems – www.lumissil.com Rev. B, 05/20/2015 1 IS31LT3353 PIN CONFIGURATION Package Pin Configuration SOT23-5 SOT89-5 LX 1 GND 2 ADJ 3 5 VIN Thermal Pad 4 ISENSE PIN DESCRIPTION No. Pin Description 1 LX Drain of power switch. 2 GND SOT23-5 SOT89-5 3 4 5 - Ground (0V). Multi-function On/Off and brightness control pin: * Leave floating for normal operation.(VADJ = VREF = 1.2V giving nominal average output current IOUT_NOM =0.1/RS) * Drive to voltage below 0.2V to turn off output current. * Drive with DC voltage (0.3V