LT3741/LT3741-1 High Power, Constant Current, Constant Voltage, Step-Down Controller FEATURESDESCRIPTION n Control Pin Provides Accurate Control of Regulated The LT®3741 and LT3741-1 are fixed frequency synchro- Output Current nous step-down DC/DC controllers designed to accurately n ±1.5% Voltage Regulation Accuracy regulate the output current at up to 20A. The average current- n ±6% Current Regulation Accuracy mode controller will maintain inductor current regulation n 6V to 36V Input Voltage Range over a wide output voltage range of 0V to (VIN – 2V). The n Wide Output Voltage Range Up to (VIN – 2V) regulated current is set by an analog voltage on the CTRL n Average Current Mode Control pins and an external sense resistor. Due to its unique n <1µA Shutdown Current topology, the LT3741 is capable of sourcing and sinking n Up to 94% Efficiency current. If sinking current is not required, or for parallel n Additional Pin for Thermal Control of Load Current applications, use the LT3741-1. The regulated voltage and n Thermally Enhanced 4mm × 4mm QFN and 20-Pin overvoltage protection are set with a voltage divider from FE Package the output to the FB pin. Soft-Start is provided to allow a gradual increase in the regulated current during startup. The switching frequency is programmable from 200kHz to APPLICATIONS 1MHz through an external resistor on the RT pin or through n General Purpose Industrial the use of the SYNC pin and an external clock signal. n Super-Cap Charging Additional Features include an accurate external reference n Applications Needing Extreme Short-Circuit Protec- voltage for use with the CTRL pins, an accurate UVLO/EN tion and/or Accurate Output Current Limit pin that allows for programmable UVLO hysteresis, and n Constant Current or Constant Voltage Source thermal shutdown. All registered trademarks and trademarks are the property of their respective owners. Protected by U.S. Patents including 7199560, 7321203 and others pending. TYPICAL APPLICATION10V/20A Constant Current, Constant Voltage Step-Down ConverterV EN/UVLO EN/UVLO V V OUT vs IOUT IN IN 14V TO 36V RT 1µF 100µF 12 82.5k SYNC HG LT3741 220nF 10 VREF CBOOT 2.2µH 10nF 2.5mΩ VOUT 8 SW 10V CTRL1 20A (V) V 6 VC CC_INT V OUT 22µF 39.2k RHOT LG 150µF 4 45.3k 5.6nF GND ×2 2 VIN = 18V CTRL2 SENSE+ VOUT = 10V SENSE– 88.7k ILIMIT = 20A R 0 NTC SS FB 0 2 4 6 8 10 12 14 16 18 20 22 10nF 12.1k IOUT (A) 3741 TA01b 3741 TA01a 37411fg For more information www.linear.com/LT3741 1 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Applications Typical Application Related Parts Features Applications Typical Application Description Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Applications Package Description Revision History Typical Application Related Parts
