LT3486 Dual 1.3A White LED Step-Up Converters with Wide Dimming FEATURES DESCRIPTION n Wide (1000:1) PWM Dimming Range with No The LT 3486 is a dual step-up DC/DC converter ColorShift specifically designed to drive up to 16 White LEDs (8 in n Independent Dimming and Shutdown Control of the series per converter) at constant current from a single LED Drivers Li-Ion cell. Series connection of the LEDs provides identi- n Drives Up to 16 White LEDs at 25mA (8 per Driver) cal LED currents resulting in uniform brightness. The two from a Single Li-Ion Cell independent converters are capable of driving asymmetric n Drives Up to 16 White LEDs at 100mA (8 per Driver) LED strings. from 12V Supply The dimming of the two LED strings can be controlled n 3% LED Current Programming Accuracy independently via the respective CTRL pins. An internal n Open LED Protection: 36V Clamp Voltage dimming system allows the dimming range to be extended n Fixed Frequency Operation: Up to 2.5MHz up to 1000:1 by feeding a PWM signal to the respective n Wide Input Voltage Range: 2.5V to 24V PWM pins. The LT3486 operating frequency can be set with n Low Shutdown Current: ICC < 1A an external resistor over a 200kHz to 2.5MHz range. A low n Overtemperature Protection 200mV feedback voltage (3% accuracy) minimizes power n Available in (5mm 3mm 0.75mm) 16-Pin DFN loss in the current setting resistor for better efficiency. and 16-Pin Thermally Enhanced TSSOP Packages Additional features include output voltage limiting when LEDs are disconnected and overtemperature protection. APPLICATIONS The LT3486 is available in a space saving 16-pin DFN n Notebook PC Display (5mm 3mm 0.75mm) and 16-pin thermally enhanced n LED Camera Light for Cell Phones TSSOP packages. n Car Dashboard Lighting L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and n ThinSOT is a trademark of Linear Technology Corporation. All other trademarks are the property Avionics Displays of their respective owners. TYPICAL APPLICATION Li-Ion Powered Driver for Camera Flash and LCD Backlighting V IN 3V TO 4.2V Efficiency vs V IN 10F 90 MOVIE MODE L1 L2 2.2F I = 175mA LED1 10H 10H 2.2F 85 8 LEDs SW1 V SW2 IN LED1 FLASH MODE AOT3218 OVP2 OVP1 80 I = 320mA LED1 25mA DIMMING 1 CTRL1 CTRL2 DIMMING 2 OFF ON REF SHDN 75 LT3486 0.1F PWM2 PWM1 70 FB1 FB2 OFF ON V GND R V C1 T C2 8 LEDS/25mA 65 R R FB2 FB1 100k 63.4k 2.8k 3 3.2 3.4 3.6 3.8 4 4.2 0.62 8.06 V (V) IN 0.1F 4.7nF 3486 TA01a 3486 TA01b 3486fe 1 EFFICIENCY (%)LT3486 ABSOLUTE MAXIMUM RATINGS (Note 1) Input Voltage (V ) ....................................................25V Operating Junction Temperature Range (Note 2) IN SHDN Voltage ...........................................................25V LT3486E ...............................................40C to 85C SW1, SW2 Voltages .................................................40V LT3486I ..............................................40C to 125C OVP1, OVP2 Voltages ...............................................40V Storage Temperature Range CTRL1, CTRL2 Voltages ............................................10V DFN ...................................................65C to 125C PWM1, PWM2 Voltages ............................................10V TSSOP ...............................................65C to 150C FB1, FB2 Voltages .....................................................10V Maximum Junction Temperature........................... 125C Lead Temperature (Soldering, 10 sec, TSSOP) ..... 300C PIN CONFIGURATION TOP VIEW TOP VIEW SW1 1 16 SW2 SW1 1 16 SW2 V 2 15 REF IN V 2 15 REF IN OVP1 3 14 OVP2 OVP1 3 14 OVP2 R 4 13 SHDN T 17 R 4 13 SHDN T 17 V 5 12 V C1 C2 V 5 12 V C1 C2 FB1 6 11 FB2 FB1 6 11 FB2 CTRL1 7 10 CTRL2 CTRL1 7 10 CTRL2 PWM1 8 9 PWM2 PWM1 8 9 PWM2 DHC PACKAGE FE PACKAGE 16-LEAD (5mm 3mm) PLASTIC DFN 16-LEAD PLASTIC TSSOP EXPOSED PAD (PIN 17) IS GND EXPOSED PAD IS GND (PIN 17) MUST BE SOLDERED TO PCB MUST BE SOLDERED TO PCB T = 125C, = 43C/W, = 4C/W JMAX JA JC T = 125C, = 38C/W, = 10C/W JMAX JA JC ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE LT3486EDHC PBF LT3486EDHC TRPBF 3486 16-Lead (5mm 3mm) Plastic DFN 40C to 85C LT3486EFE PBF LT3486EFE TRPBF 3486EFE 16-Lead Plastic TSSOP 40C to 85C LT3486IFE PBF LT3486IFE TRPBF 3486IFE 16-Lead Plastic TSSOP 40C to 125C LEAD BASED FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE LT3486EDHC LT3486EDHC TR 3486 16-Lead (5mm 3mm) Plastic DFN 40C to 85C LT3486EFE LT3486EFE TR 3486EFE 16-Lead Plastic TSSOP 40C to 85C LT3486IFE LT3486IFE TR 3486IFE 16-Lead Plastic TSSOP 40C to 125C Consult LTC Marketing for parts specified with wider operating temperature ranges. For more information on lead free part marking, go to: