POWER LOSS (W) LT3579/LT3579-1 6A Boost/Inverting DC/DC Converter with Fault Protection FEATURES DESCRIPTION n 6A, 42V Combined Power Switch The LT 3579 is a PWM DC/DC converter with built-in fault n Output Short Circuit Protection protection features to aid in protecting against output shorts, n Wide Input Range: 2.5V to 16V Operating, input/output overvoltage, and overtemperature conditions. 40V Maximum Transient The part consists of a 42V master switch, and a 42V slave n LT3579-1: Dual-Phase Capable switch that can be tied together for a total current limit of 6A. n Master/Slave (3.4A/2.6A) Switch Design The LT3579 is ideal for many local power supply designs. It n User Configurable Under voltage Lockout can be easily configured in Boost, SEPIC, Inverting, or Flyback n Easily Configurable as a Boost, SEPIC, Inverting, or configurations, and is capable of generating 12V at 1.7A, or Flyback Converter 12V at 1.2A from a 5V input. In addition, the LT3579s slave n Low V Switch: 250mV at 5.5A (Typical) CESAT switch allows the part to be configured in high voltage, high n Can Be Synchronized to External Clock power charge pump topologies that are very efficient and n Can Synchronize other Switching Regulators require fewer components than traditional circuits. n High Gain SHDN Pin Accepts Slowly Varying Input The LT3579s switching frequency range can be set bet- Signals n ween 200kHz and 2.5MHz. The part may be clocked inter- 20-Lead TSSOP and 20-Pin 4mm 5mm QFN nally at a frequency set by the resistor from the RT pin to Packages ground, or it may be synchronized to an external clock. A buffered version of the clock signal is driven out of APPLICATIONS the CLKOUT pin, and may be used to synchronize other compatible switching regulator ICs to the LT3579. n Local Power Supply n Vacuum Fluorescent Display (VFD) Bias Supplies The LT3579 also features innovative SHDN pin circuitry n TFT-LCD Bias Supplies that allows for slowly varying input signals and an adjust- n Automotive Engine Control Unit (ECU) Power able undervoltage lockout function. Additional features All registered trademarks and trademarks are the property of their respective owners. Protected such as frequency foldback and soft-start are integrated. by U.S. Patents, including 7579816. The LT3579 is available in 20-lead TSSOP and 20-pin 4mm 5mm QFN packages. TYPICAL APPLICATION Efficiency and Power Loss 100 3.2 1MHz, 5V to 12V Boost Converter with Output Short Circuit Protection 90 2.8 2.2H V OUT V IN 12V 5V 80 2.4 1.7A 10F SW1 SW2 70 2.0 130k 6.3k 10F FB V IN 60 1.6 22F 100k FAULT GATE V IN 50 1.2 LT3579 200k TEMPERATURE SHDN CLKOUT MONITOR 40 0.8 V RT C 30 0.4 SYNC GND SS 8k 86.6k 0.1F 47pF 2.2nF 20 0 0 0.25 0.5 0.75 1 1.25 1.5 1.75 2 35791 TA01 LOAD CURRENT (A) 35791 TA02 Rev. BRev. B 11 Document Feedback For more information www.analog.com EFFICIENCY (%)LT3579/LT3579-1 ABSOLUTE MAXIMUM RATINGS (Note 1) V Voltage ................................................. 0.3V to 40V FAULT ......................................................... 0.3V to 40V IN SW1/SW2 Voltage ..................................... 0.4V to 42V FAULT Current .....................................................0.5mA R Voltage .................................................... 0.3V to 5V CLKOUT ....................................................... 0.3V to 3V T SS, FB Voltage ......................................... 0.3V to 2.5V CLKOUT Current..................................................... 1mA V Voltage ................................................... 0.3V to 2V Operating Junction Temperature Range C SHDN Voltage ............................................ 0.3V to 40V LT3579E (Notes 2, 4) ......................... 40C to 125C SYNC Voltage ............................................ 0.3V to 5.5V LT3579I (Notes 2, 4) .......................... 40C to 125C GATE Voltage ............................................. 0.3V to 80V Storage Temperature Range ..................65C to 150C PIN CONFIGURATION TOP VIEW TOP VIEW FB 1 20 SYNC V 2 19 SS C 20 19 18 17 GATE 3 18 R T GATE 1 16 R T FAULT 4 17 SHDN FAULT 2 15 SHDN V 5 16 CLKOUT V CLKOUT IN 21 3 14 IN 21 GND GND SW1 6 15 SW2 SW1 4 13 SW2 SW1 5 12 SW2 SW1 7 14 SW2 SW1 6 11 SW2 SW1 8 13 SW2 SW1 9 12 SW2 7 8 9 10 SW1 10 11 SW2 FE PACKAGE UFD PACKAGE 20-LEAD PLASTIC TSSOP 20-LEAD (4mm 5mm) PLASTIC QFN T = 125C, = 38C/W, = 10C/W JMAX JA JC T = 125C, = 34C/W, = 2.7C/W JMAX JA JC EXPOSED PAD (PIN 21) IS GND, MUST BE SOLDERED TO PCB EXPOSED PAD (PIN 21) IS GND, MUST BE SOLDERED TO PCB ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LT3579EFE PBF LT3579EFE TRPBF LT3579FE 20-Lead Plastic TSSOP 40C to 125C LT3579IFE PBF LT3579IFE TRPBF LT3579FE 20-Lead Plastic TSSOP 40C to 125C LT3579EUFD PBF LT3579EUFD TRPBF 3579 20-Lead (4mm 5mm) Plastic QFN 40C to 125C LT3579IUFD PBF LT3579IUFD TRPBF 3579 20-Lead (4mm 5mm) Plastic QFN 40C to 125C LT3579EFE-1 PBF LT3579EFE-1 TRPBF LT3579FE-1 20-Lead Plastic TSSOP 40C to 125C LT3579IFE-1 PBF LT3579IFE-1 TRPBF LT3579FE-1 20-Lead Plastic TSSOP 40C to 125C LT3579EUFD-1 PBF LT3579EUFD-1 TRPBF 35791 20-Lead (4mm 5mm) Plastic QFN 40C to 125C LT3579IUFD-1 PBF LT3579IUFD-1 TRPBF 35791 20-Lead (4mm 5mm) Plastic QFN 40C to 125C Contact the factory for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container. Tape and reel specifications. Some packages are available in 500 unit reels through designated sales channels with TRMPBF suffix. Rev. B 2 For more information www.analog.com SW1 FB V GND C GND SS SW2 SYNC