LT3959 Wide Input Voltage Range Boost/SEPIC/Inverting Converter with 6A, 40V Switch FeaTuresDescripTion n Wide VIN Range: 1.6V (2.5V Start-Up) to 40V The LT®3959 is a wide input range, current mode, DC/DC 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 PGOODOutput 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) with One External Resistor ply provided from VIN or DRIVE. The fixed frequency, 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 < 1µA frequency of LT3959 can be set over a 100kHz to 1MHz n INTVCC Regulator Supplied from VIN or DRIVE range with an external resistor, or can be synchronized n Programmable Input Undervoltage Lockout with Hysteresis to an external clock using the SYNC pin. n Thermally Enhanced QFN (5mm × 6mm) and TSSOP The LT3959 features soft-start and frequency foldback Packages functions to limit inductor current during start-up and applicaTions output short-circuit. A window comparator on the FBX pin reports via the PGOOD pin, providing output voltage n Automotive status indication. n Telecom L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and ThinSOT are trademarks of Linear Technology Corporation. All other trademarks are the n Industrial property of their respective owners. Protected by U.S. Patents, including 7825665. Typical applicaTion2.5V to 24V Input, 12V Output SEPIC ConverterExcellent for Automotive 12V Post RegulatorEfficiency vs Output Current 100 4.7µF VIN = 12V 50V L1A VOUT 95 VIN 12V 2.5V TO 500mA AT V 90 C IN = 2.5V 24V IN 22µF 1.5A AT V 124k V C IN > 8V IN SW OUT 85 50V 47µF ×2 EN_UVLO L1B 16V 80 ×2 150k 121k LT3959 GND EFFICIENCY (%) 75 70 PGOOD DRIVE TIE TO SGND 65 SYNC IF NOT USED 105K 60 RT 0 200 400 600 800 1000 FBX SS OUTPUT CURRENT (mA) VC SGND GNDK INTV 3959 TA01b CC 27.4k 300kHz 0.1µF 7.5k 15.8K 22nF 4.7µF 3959 TA01a 3959fa For more information www.linear.com/LT3959 1 Document Outline Features Description Applications Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Applications Information Typical Applications Package Description Revision History Related Parts
