LT3491EDC#TRPBF Analog Devices

LT3491 White LED Driver with Integrated Schottky in SC70 and 2mm 2mm DFN FEATURES DESCRIPTIO Drives Up to Six White LEDs from a 3V Supply The LT 3491 is a fixed frequency step-up DC/DC converter High Side Sense Allows One Wire Current Source specifically designed to drive up to six white LEDs in series Internal Schottky Diode from a Li-Ion cell. Series connection of the LEDs provides One Pin Dimming and Shutdown identical LED currents resulting in uniform brightness and 27V Open LED Protection eliminating the need for ballast resistors. The device 2.3MHz Switching Frequency features a unique high side LED current sense that enables 5% Reference Accuracy the part to function as a one wire current source one V Range: 2.5V to 12V side of the LED string can be returned to ground anywhere, IN Requires Only 1F Output Capacitor allowing a simpler one wire LED connection. Traditional TM Wide 300:1 True Color PWM Dimming Range LED drivers use a grounded resistor to sense LED current, 8-Lead SC70 Package requiring a 2-wire connection to the LED string. Low Profile 6-Lead DFN Package The 2.3MHz switching frequency allows the use of tiny (2mm 2mm 0.75mm) inductors and capacitors. A single pin performs both U shutdown and accurate LED dimming control. Few exter- APPLICATIO S nal components are needed: open-LED protection and the Cellular Phones Schottky diode are all contained inside the tiny SC70 and PDAs, Handheld Computers 2mm 2mm DFN packages. With such a high level of Digital Cameras integration, the LT3491 provides a high efficiency LED MP3 Players driver solution in the smallest of spaces. GPS Receivers , LTC, LT and LTM are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. TYPICAL APPLICATIO Efficiency Li-Ion Driver for Four White LEDs SHUTDOWN AND 80 V = 3.6V IN DIMMING CONTROL 4 LEDs 75 CTRL 70 V IN V CAP IN 3V TO 5V 65 R L1 SENSE LT3491 10 10H 60 SW LED 55 GND C2 1F C1 50 1F 45 40 0 5 10 15 20 3491 TA01a LED CURRENT (mA) C1: TAIYO YUDEN LMK212BJ105MD 3491 TA01b C2: TAIYO YUDEN GMK316BJ105ML L1: MURATA LQH32CN100 3491fa 1 EFFICIENCY (%) U ULT3491 ABSOLUTE AXI U RATI GS (Note 1) Input Voltage (V ) ................................................. 12V LED Voltage ............................................................ 32V IN SW Voltage ............................................................. 32V Operating Temperature Range (Note 2) .. 40C to 85C CAP Voltage ............................................................ 32V Maximum Junction Temperature ......................... 125C CTRL Voltage .......................................................... 12V Storage Temperature Range ................ 65C to 150C Lead Temperature (Soldering, 10sec, SC-70) ......... 300C UUW PACKAGE/ORDER I FOR ATIO TOP VIEW TOP VIEW V 1 6 CTRL IN SW 1 8 CAP GND 2 7 5 LED GND 2 7 LED GND 3 6 CTRL SW 3 4 CAP GND 4 5 V IN SC8 PACKAGE DC PACKAGE 8-LEAD PLASTIC SC70 6-LEAD (2mm 2mm) PLASTIC DFN T = 125C, = 270C/ W JMAX JA T = 125C, = 102C/W, = 20C/ W JMAX JA JC EXPOSED PAD (PIN 7) SHOULD BE CONNECTED TO PCB GROUND ORDER PART NUMBER DC PART MARKING ORDER PART NUMBER DC PART MARKING LT3491EDC LCHJ LT3491ESC8 LBXQ Order Options Tape and Reel: Add TR Lead Free: Add PBF Lead Free Tape and Reel: Add TRPBF Lead Free Part Marking: