LT3741
LT3741-1

PRODUCTION

High Power, Constant Current, Constant Voltage, Step-Down Controller

Part Models: 16
1ku List Price: Starting From $4.72

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Overview

Control Pin Provides Accurate Control of Regulated Output Current
±1.5% Voltage Regulation Accuracy
±6% Current Regulation Accuracy
6V to 36V Input Voltage Range
Wide Output Voltage Range Up to (V_IN – 2V)
Average Current Mode Control
<1μA Shutdown Current
Up to 94% Efficiency
Additional Pin for Thermal Control of Load Current
Thermally Enhanced 4mm × 4mm QFN and 20-Pin FE Package

The LT3741 and LT3741-1 are fixed frequency synchronous step-down DC/DC controllers designed to accurately regulate the output current at up to 20A. The average current-mode controller will maintain inductor current regulation over a wide output voltage range of 0V to (V_IN – 2V). The regulated current is set by an analog voltage on the CTRL pins and an external sense resistor. Due to its unique topology, the LT3741 is capable of sourcing and sinking current. If sinking current is not required, or for parallel applications, use the LT3741-1. The regulated voltage and overvoltage protection are set with a voltage divider from 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 1MHz through an external resistor on the RT pin or through the use of the SYNC pin and an external clock signal.

Additional Features include an accurate external reference voltage for use with the CTRL pins, an accurate UVLO/EN pin that allows for programmable UVLO hysteresis, and thermal shutdown.

Applications

General Purpose Industrial
Super-Cap Charging
Applications Needing Extreme Short-Circuit Protection and/or Accurate Output Current Limit
Constant Current or Constant Voltage Source

Part Models: 16
1ku List Price: Starting From $4.72

Documentation

ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal. View our quality and reliability program and certifications for more information.

Part Model	Pin/Package Drawing	Documentation	CAD Symbols, Footprints, and 3D Models
LT3741EFE#PBF	20-Lead TSSOP w/ EP	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LT3741EFE#TRPBF	20-Lead TSSOP w/ EP	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LT3741EFE-1#PBF	20-Lead TSSOP w/ EP	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LT3741EFE-1#TRPBF	20-Lead TSSOP w/ EP	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LT3741EUF#PBF	20-Lead QFN (4mm x 4mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LT3741EUF#TRPBF	20-Lead QFN (4mm x 4mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LT3741EUF-1#PBF	20-Lead QFN (4mm x 4mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LT3741EUF-1#TRPBF	20-Lead QFN (4mm x 4mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LT3741IFE#PBF	20-Lead TSSOP w/ EP	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LT3741IFE#TRPBF	20-Lead TSSOP w/ EP	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LT3741IFE-1#PBF	20-Lead TSSOP w/ EP	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LT3741IFE-1#TRPBF	20-Lead TSSOP w/ EP	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LT3741IUF#PBF	20-Lead QFN (4mm x 4mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LT3741IUF#TRPBF	20-Lead QFN (4mm x 4mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LT3741IUF-1#PBF	20-Lead QFN (4mm x 4mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LT3741IUF-1#TRPBF	20-Lead QFN (4mm x 4mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys

Part Models	Product Lifecycle	PCN

Apr 6, 2022 - 22_0068 Laser Top Mark for ETSSOP and TSSOP Packages Assembled in ADPG [PNG] and UTL
		PCN22_0068_Form Material_Report Delta Qualification Matrix
LT3741EFE#PBF	PRODUCTION
LT3741EFE#TRPBF	PRODUCTION
LT3741EFE-1#PBF	PRODUCTION
LT3741EFE-1#TRPBF	PRODUCTION
LT3741IFE#PBF	PRODUCTION
LT3741IFE#TRPBF	PRODUCTION
LT3741IFE-1#PBF	PRODUCTION
LT3741IFE-1#TRPBF	PRODUCTION
Jan 20, 2022 - 21_0269 Addition of Alternate Assembly Site ASE Taiwan for Select LFCSP Products
		PCN21_0269_Form Material_Report Detailed Change Description Qualification Results Summary
LT3741EUF#PBF	PRODUCTION
LT3741EUF#TRPBF	PRODUCTION
LT3741EUF-1#PBF	PRODUCTION
LT3741EUF-1#TRPBF	PRODUCTION
LT3741IUF#PBF	PRODUCTION
LT3741IUF#TRPBF	PRODUCTION
LT3741IUF-1#PBF	PRODUCTION
LT3741IUF-1#TRPBF	PRODUCTION

This is the most up-to-date revision of the Data Sheet.

Software Resources

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Hardware Ecosystem

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Circuit Monitors 1
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Power System Management (PSM) & Sequencers 1
LTC2974	RECOMMENDED FOR NEW DESIGNS	4-Channel PMBus Power System Manager Featuring Accurate Output Current Measurement
Protection Switches & Controllers 1
LT4363	RECOMMENDED FOR NEW DESIGNS	High Voltage Surge Stopper with Current Limit
Switching Regulators & Controllers 1
LTC3880	RECOMMENDED FOR NEW DESIGNS	Dual Output PolyPhase Step-Down DC/DC Controller with Digital Power System Management

Tools & Simulations

LTspice 3

Models for the following parts are available in LTspice:

LT3741

LTspice® is a powerful, fast and free simulation software, schematic capture and waveform viewer with enhancements and models for improving the simulation of analog circuits.

Evaluation Kits

LT3741EFE Demo Board | 120W LED Driver, 12V ≤ VIN ≤ 24V, CC/CV Synchronous Step-Down Controller, VOUT = 6V @ 20A

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Product Details

Demonstration circuit 1602 is a High Power Constant Current, Constant Voltage Synchronous Buck Controller featuring the LT3741. The demo board is optimized for 20A output from a 12V input. Being an LED driver, the output current is being regulated until the output voltage reaches a programmed voltage limit. The voltage limit on this demo board is set to around 6V by R11 and R14. The 6V is chosen because of the 10V voltage rating of the output capacitors. Higher output voltage can be easily achieved with higher voltage rated output capacitors.

The ideal load to be used with this demo board is a single LED, such as PT120 from Luminus Devices. Smaller LEDs may not be able to handle the high current, even for a short period of time. At 20A, the demo circuit can operate continuously. However, it is necessary to mount the LED load on a proper heat sink and possibly with a fan to avoid exceed its maximum temperate rating.