LT3959 Wide Input Voltage Range Boost/SEPIC/Inverting Converter with 6A, 40V Switch Fea T Descrip T n Wide V Range: 1.6V (2.5V Start-Up) to 40V The LT 3959 is a wide input range, current mode, DC/DC IN n Positive or Negative Output Voltage Programming controller which is capable of regulating either positive or with a Single Feedback Pin negative output voltages from a single feedback pin. It can n PGOOD Output Voltage Status Report be configured as a boost, SEPIC or inverting converter. n Internal 6A/40V Power Switch It features an internal low side N-channel MOSFET rated n Programmable Soft-Start for 6A at 40V and driven from an internal regulated sup- n Programmable Operating Frequency (100kHz to 1MHz) ply provided from V or DRIVE. The fixed frequency, IN with One External Resistor current-mode architecture results in stable operation over n Synchronizable to an External Clock a wide range of supply and output voltages. The operating n Low Shutdown Current < 1A frequency of LT3959 can be set over a 100kHz to 1MHz n INTV Regulator Supplied from V or DRIVE CC IN range with an external resistor, or can be synchronized n Programmable Input Undervoltage Lockout with to an external clock using the SYNC pin. Hysteresis n The LT3959 features soft-start and frequency foldback Thermally Enhanced QFN (5mm 6mm) and TSSOP functions to limit inductor current during start-up and Packages output short-circuit. A window comparator on the FBX a T pin reports via the PGOOD pin, providing output voltage status indication. n Automotive L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and n Telecom ThinSOT are trademarks of Linear Technology Corporation. All other trademarks are the n property of their respective owners. Protected by U.S. Patents, including 7825665. Industrial Typical a T 2.5V to 24V Input, 12V Output SEPIC Converter Efficiency vs Output Current Excellent for Automotive 12V Post Regulator 100 V = 12V 4.7F IN 50V V 95 L1A OUT V 12V IN 2.5V TO 90 500mA AT V = 2.5V IN C IN 24V 1.5A AT V > 8V IN C 22F OUT 124k V SW IN 85 47F 50V L1B EN UVLO 16V 2 80 2 150k 121k LT3959 GND 75 70 PGOOD DRIVE 65 TIE TO SGND SYNC IF NOT USED 105K 60 RT 0 200 400 600 800 1000 FBX SS OUTPUT CURRENT (mA) V SGND GNDK INTV 3959 TA01b C CC 27.4k 0.1F 7.5k 15.8K 300kHz 22nF 4.7F 3959 TA01a 3959fa 1 For more information www.linear.com/LT3959 EFFICIENCY (%) ion pplica ions pplica ion uresLT3959 a Te Maxi Mu M r a T (Note 1) V ............................................................................40V V , SS .........................................................................3V IN C EN/UVLO (Note 2) .....................................................40V RT ............................................................................1.5V DRIVE .......................................................................40V GND, GNDK to SGND .............................................0.3V PGOOD ......................................................................40V FBX ................................................................. 3V to 3V SW ............................................................................40V Operating Junction Temperature Range (Note 3) INTV ........................................................................8V LT3959E/LT3959I .............................. 40C to 125C CC SYNC ..........................................................................8V Storage Temperature Range .................. 65C to 125C p c F T TOP VIEW TOP VIEW NC 1 38 NC NC 2 37 NC 36 35 34 33 32 31 30 NC 3 36 NC NC 1 28 DRIVE V 4 35 NC C NC 2 27 V IN FBX 5 34 EN/UVLO 37 NC 3 SS 6 33 V SGND IN SGND 4 25 EN/UVLO RT 7 32 DRIVE 24 SGND 39 SYNC 8 31 INTV CC SGND NC 6 23 NC PGOOD 9 30 NC SGND 10 29 SGND 38 SW 8 21 SW SW NC 11 28 NC SW 9 20 SW SW 12 27 SW NC 10 40 NC 13 26 NC 12 13 14 15 16 17 SW NC 14 25 NC SW 15 24 SW NC 16 23 NC UHEMA PACKAGE 36-LEAD (5mm 6mm) PLASTIC QFN GNDK 17 22 GND T =125C, = 42C/W, = 3C/W JMAX JA JC GND 18 21 GND EXPOSED PAD (PIN 37) IS SGND, MUST BE SOLDERED TO SGND PLANE GND 19 20 GND EXPOSED PAD (PIN 38) IS SW, MUST BE SOLDERED TO SW PLANE FE PACKAGE 38-LEAD PLASTIC TSSOP T =125C, = 42C/W, = 3C/W JMAX JA JC EXPOSED PAD (PIN 39) IS SGND, MUST BE SOLDERED TO SGND PLANE EXPOSED PAD (PIN 40) IS SW, MUST BE SOLDERED TO SW PLANE 3959fa 2 For more information www.linear.com/LT3959 INTV CC GNDK PGOOD GND SYNC GND RT GND SS GND FBX GND V C ion igura on in ings bsolu