LT3479 3A, Full Featured DC/DC Converter with Soft-Start and Inrush Current Protection FEATURES DESCRIPTION n Wide Input Voltage Range: 2.5V to 24V The LT 3479 is a current mode, xed frequency step-up n 3A, 42V Internal Switch DC/DC converter with an internal 3A, 42V switch. Ef cien- n High Ef ciency Power Conversion: Up to 89% cies of up to 89% can be achieved in typical applications. It n Soft-Start features a programmable soft-start function to limit induc- n Frequency Set by External Resistor: 200kHz to tor current during start-up and inrush current protection 3.5MHz to protect the LT3479 during shorts and line transients. n Protection Against Input Short Circuits and Both inputs of the error ampli er are available to the user Hot Plugging allowing positive and negative output voltages. Through n Low V Switch: 0.3V at 2.5A (Typical) an external resistor, the user can program the switch- CESAT n Capable of Positive and Negative Outputs ing frequency from 200kHz to 3.5MHz. The low pro le n Available in Thermally Enhanced 14-Lead (0.75mm) 14-pin, 4mm 3mm DFN package provides (4mm 3mm) DFN and 16-Lead TSSOP Packages excellent thermal performance in a small footprint. The LT3479 is also available in a thermally enhanced 16-pin APPLICATIONS TSSOP package. L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear n High Power LED Driver Technology Corporation. All other trademarks are the property of their respective owners. n DSL Modems n Distributed Power TYPICAL APPLICATION 5V to 12V Boost Converter 5V to 12V Ef ciency 4.7H 90 V OUT V IN 12V 5V 0.8A 85 2.2F 10F 200k V V L SW IN S FBN 80 SHDN 23.2k LT3479 75 V REF SS 70 FBP 10nF R GND V T C 65 10k 17.8k 2.2nF 60 0 0.2 0.4 0.6 0.8 3479 TA01 I (A) OUT 3479 TA02 3479fc 1 EFFICIENCY (%)LT3479 ABSOLUTE MAXIMUM RATINGS (Note 1) SW, L, V Voltages ................................................... 42V Operating Temperature Range (Note 2).... 40C to 85C S V , SHDN Voltages ................................................. 24V Storage Temperature Range ................... 65C to 125C IN FBP, FBN, V , R , V Voltages ................................. 2V Lead Temperature (Soldering, 10 sec) REF T C Junction Temperature .......................................... 125C TSSOP ..............................................................300C PIN CONFIGURATION TOP VIEW TOP VIEW SW 1 16 GND SW 1 14 GND SW 2 15 GND SW 2 13 GND L 3 14 GND L 3 12 SS V 4 13 SS S V 4 15 11 V 17 S C V 5 12 V IN C V 5 10 FBN IN R 6 11 FBN T R 6 9 FBP T SHDN 7 10 FBP SHDN 7 8 V REF GND 8 9 V REF DE14 PACKAGE 14-LEAD (4mm s 3mm) PLASTIC DFN FE PACKAGE T = 125C, = 43C/W 16-LEAD PLASTIC TSSOP JMAX JA EXPOSED PAD (PIN 15) IS PGND (MUST BE SOLDERED TO PCB) T = 125C, = 38C/W JMAX JA EXPOSED PAD (PIN 17) IS PGND (MUST BE SOLDERED TO PCB) ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE LT3479EDE PBF LT3479EDE TRPBF 3479 40C to 85C 14-Lead (4mm 3mm) Plastic DFN LT3479EFE PBF LT3479EFE TRPBF 3479EFE 16-Lead Plastic TSSOP 40C to 85C LEAD BASED FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE LT3479EDE LT3479EDE TR 3479 40C to 85C 14-Lead (4mm 3mm) Plastic DFN LT3479EFE LT3479EFE TR 3479EFE 16-Lead Plastic TSSOP 40C to 85C Consult LTC Marketing for parts speci ed with wider operating temperature ranges. For more information on lead free part marking, go to: