LT3741/LT3741-1 High Power, Constant Current, Constant Voltage, Step-Down Controller Fea T Descrip T 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 (V 2V). The IN n Wide Output Voltage Range Up to (V 2V) regulated current is set by an analog voltage on the CTRL IN n Average Current Mode Control pins and an external sense resistor. Due to its unique n <1A 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 overvoltage protection are set with a voltage divider from Thermally Enhanced 4mm 4mm QFN and 20-Pin the output to the FB pin. Soft-Start is provided to allow a FE Package gradual increase in the regulated current during startup. The switching frequency is programmable from 200kHz to a T 1MHz through an external resistor on the RT pin or through n the use of the SYNC pin and an external clock signal. General Purpose Industrial n Super-Cap Charging Additional Features include an accurate external reference n Applications Needing Extreme Short-Circuit voltage for use with the CTRL pins, an accurate UVLO/EN Protection and/or Accurate Output Current Limit pin that allows for programmable UVLO hysteresis, and n Constant Current or Constant Voltage Source thermal shutdown. L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents including 7199560, 7321203 and others pending. Typical a T 10V/20A Constant Current, Constant Voltage Step-Down Converter V vs I V IN OUT OUT EN/UVLO EN/UVLO V IN 14V TO 36V 12 RT 1F 100F SYNC 82.5k HG 10 LT3741 220nF V REF CBOOT 2.2H V 10nF 2.5m OUT 8 10V SW 20A CTRL1 6 V CC INT VC 22F 39.2k 4 R LG HOT 150F 45.3k 2 5.6nF GND V = 18V 2 IN + CTRL2 SENSE V = 10V OUT 88.7k I = 20A SENSE LIMIT 0 R NTC SS FB 0 2 4 6 8 10 12 14 16 18 20 22 10nF 12.1k I (A) OUT 3741 TA01b 3741 TA01a 37411fe 1 For more information www.linear.com/LT3741 V (V) OUT ion pplica ions pplica ion uresLT3741/LT3741-1 a Te m aximum r a T (Note 1) V Voltage ................................................................40V RT Voltage...................................................................3V IN EN/UVLO Voltage ........................................................6V FB Voltage ...................................................................3V V Voltage ................................................................3V SS Voltage ..................................................................6V REF CTRL1 and CTRL2 Voltage ..........................................3V V Voltage ...........................................................6V CC INT + SENSE Voltage ........................................................40V SYNC Voltage ..............................................................6V SENSE Voltage ........................................................40V Storage Temperature Range ................... 65C to 150C VC Voltage ..................................................................3V Lead Temperature (Soldering, 10 sec) SW Voltage ...............................................................40V TSSOP .............................................................. 300C CBOOT ......................................................................46V p in c F T TOP VIEW TOP VIEW V 1 20 LG CC INT GND 2 19 CBOOT 20 19 18 17 16 V 3 18 SW IN EN/UVLO 1 15 HG EN/UVLO 4 17 HG V 2 14 GND REF V 5 16 GND REF 21 21 CTRL2 3 13 SYNC GND GND CTRL2 6 15 SYNC GND 4 RT 12 GND 7 14 RT CTRL1 GND 5 11 CTRL1 8 13 VC 6 7 8 9 10 SS 9 12 SENSE + FB 10 11 SENSE FE PACKAGE 20-LEAD PLASTIC TSSOP UF PACKAGE 20-LEAD (4mm 4mm) PLASTIC QFN T = 125C, q = 38C/W JMAX JA EXPOSED PAD (PIN 21) IS GND, MUST BE SOLDERED TO PCB T = 125C, q = 37C/W JMAX JA EXPOSED PAD (PIN 21) IS GND, MUST BE SOLDERED TO PCB o r Der i n F T LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE 20-Lead (4mm 4mm) Plastic QFN LT3741EUF PBF LT3741EUF TRPBF 3741 40C to 125C 20-Lead (4mm 4mm) Plastic QFN LT3741IUF PBF LT3741IUF TRPBF 3741 40C to 125C LT3741EFE PBF LT3741EFE TRPBF LT3741FE 20-Lead Plastic TSSOP 40C to 125C LT3741IFE PBF LT3741IFE TRPBF LT3741FE 20-Lead Plastic TSSOP 40C to 125C LT3741EUF-1 PBF LT3741EUF-1 TRPBF 37411 40C to 125C 20-Lead (4mm 4mm) Plastic QFN LT3741IUF-1 PBF LT3741IUF-1 TRPBF 37411 20-Lead (4mm 4mm) Plastic QFN 40C to 125C LT3741EFE-1 PBF LT3741EFE-1 TRPBF LT3741FE-1 20-Lead Plastic TSSOP 40C to 125C LT3741IFE-1 PBF LT3741IFE-1 TRPBF LT3741FE-1 20-Lead Plastic TSSOP 40C to 125C Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container. Consult LTC Marketing for information on non-standard lead based finish parts. For more information on lead free part marking, go to: