LT3598 6-String 30mA LED Driver with 1.5% Current Matching FEATURES DESCRIPTION n True Color PWM Dimming Delivers Up to 3000:1 The LT 3598 is a xed frequency step-up DC/DC converter Dimming Ratio designed to drive up to six strings of LEDs at an output n Drives Six Strings of LEDs at Up to 30mA voltage up to 44V. LED dimming can be achieved with n 1.5% Accurate LED Current Matching analog dimming on the CTRL pin, and with pulse width n Wide Input Voltage Range: 3.2V to 30V modulation dimming on the PWM pin. The LT3598 n Output Voltage Up to 44V accurately regulates LED current even when the input n Regulates Current Even When V > V voltage is higher than the LED output voltage. The switching IN OUT n Disconnects LEDs in Shutdown frequency is programmable from 200kHz to 2.5MHz n Programmable Open LED Protection (Regulated) through an external resistor. n OPENLED Alert Pin Additional features include programmable overvoltage n Programmable LED Current Derating protection, switching frequency synchronization to an n Adjustable Frequency: 200kHz to 2.5MHz external clock, LED current derating based on junction n Synchronizable to an External Clock temperature and/or LED temperature, LED string disable n Parallel Channels for Higher Current per LED String control, OPENLED alert pin and output voltage limiting n Thermally Enhanced 4mm 4mm QFN and 24-Lead when all LED strings are disconnected. The LT3598 is TSSOP Packages available in a thermally enhanced 24-lead (4mm 4mm) QFN and 24-lead TSSOP packages. APPLICATIONS L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear n Technology Corporation. True Color PWM is a trademark of Linear Technology Corporation. Notebook Computer Display All other trademarks are the property of their respective owners. Protected by U.S. Patents n Medium Size Displays including 7199560, 7321203. n Automotive LCD Display TYPICAL APPLICATION 90% Ef cient LED Driver for 60 White LEDs LED Current Matching PV IN 10H 8V TO 40V 1.5 ALL SIX LED STRINGS 2.2F 4.7F SW V OUT 1.0 V IN V V O SW IN 5V 1.00M 0.5 2.2F 100k OPENLED FB 0 SHDN SHDN 30.9k PWM PWM 0.5 LT3598 SYNC SYNC RT 1.0 51.1k V REF 1.5 10k 50 2505250 75 100 125 LED1 CTRL LED2 TEMPERATURE (C) LED3 3598 TA01b 20mA LED4 100k LED5 LED6 T I SS GND V 60.4k SET SET C 10nF 2.61k 47pF 100k 14.7k 15nF 3598 TA01a 3598fb 1 MATCHING (%)LT3598 ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (Note 1) SHDN ................................................................V + 3V V , FB Voltage..........................................................6V IN REF V , OPENLED ........................................................... 30V I , T ..................................................................... 6V IN SET SET SW Voltage ...............................................................45V Operating Junction Temperature Range V , V Voltage .................................................44V (Note 2) ..................................................40C to 125C OUT O SW LED1 to LED6 ............................................................44V Maximum Junction Temperature........................... 125C PWM, SYNC, CTRL, RT, SS, V ................................... 6V Storage Temperature Range ...................65C to 150C C TOP VIEW TOP VIEW 1 V SW 24 IN 2 SHDN V 23 OUT 24 23 22 21 20 19 3 GND V 22 O SW LED1 1 18 V 4 V LED1 21 REF REF LED2 2 17 SS 5 SS LED2 20 LED3 RT 3 16 6 RT LED3 19 25 25 LED4 4 15 PWM 7 PWM LED4 18 LED5 5 14 SYNC 8 SYNC LED5 17 LED6 6 13 NC 9 NC LED6 16 7 8 9 10 11 12 10 T OPENLED 15 SET 11 FB I 14 SET 12 V CTRL 13 C UF PACKAGE FE PACKAGE 24-LEAD (4mm 4mm) PLASTIC QFNs 24-LEAD PLASTIC TSSOP T = 125C, = 38C/W JMAX JA T = 125C, = 37C/W JMAX JA EXPOSED PAD (PIN 25) IS PGND, MUST BE SOLDERED TO PCB EXPOSED PAD (PIN 25) IS GND, MUST BE SOLDERED TO PCB ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LT3598EUF PBF LT3598EUF TRPBF 3598 24-Lead (4mm 4mm) Plastic QFN 40C to 125C LT3598IUF PBF LT3598IUF TRPBF 3598 24-Lead (4mm 4mm) Plastic QFN 40C to 125C LT3598EFE PBF LT3598EFE TRPBF LT3598 24-Lead Plastic TSSOP 40C to 125C LT3598IFE PBF LT3598IFE TRPBF LT3598 24-Lead Plastic TSSOP 40C to 125C Consult LTC Marketing for parts speci ed with wider operating temperature ranges. *The temperature grade is identi ed by a label on the shipping container. Consult LTC Marketing for information on non-standard lead based nish parts. For more information on lead free part marking, go to: