LT3740

PRODUCTION

Wide Operating Range, Valley Mode, No R_SENSE^™ Synchronous Step-Down Controller

Part Models: 2
1ku List Price: Starting From $2.36

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Overview

Wide V_IN Range: 2.2V to 22V
Internal Boost Provides 6V Gate Drive For V_IN Down to 2.2V
No Sensing Resistor Required
Dual N-Channel MOSFET Synchronous Drive
Valley Current Mode Control
Optimized for High Step-Down Ratio
Power Good Output Voltage Monitor
0.8V Reference
Three Pin-Selected Current Limit Levels
Constant Switching Frequency: 300kHz
Programmable Soft-Start
Output Voltage Tracking
Available in 16-Pin 5mm × 3mm DFN

The LT3740 is a synchronous step-down switching regulator controller that drives N-channel power MOSFET stages. The controller uses valley current mode architecture to achieve very low duty cycles with excellent transient response without requiring a sense resistor.

The LT3740 includes an internal step-up converter to provide a bias 7.8V higher than the input voltage for the drive. This enables the part to work from an input voltage as low as 2.2V.

The XREF pin is an external reference input that allows the user to override the internal 0.8V feedback reference with any lower value, allowing full control of the output voltage during operation, output voltage tracking or soft-start.

The LT3740 has three current limit levels that can be chosen by connecting the RANGE pin to ground, open, and input respectively.

Applications

Notebook and Palmtop Computers, PDA
Portable Instruments
Distributed Power Systems

Part Models: 2
1ku List Price: Starting From $2.36

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
LT3740EDHC#PBF	16-Lead DFN (5mm x 3mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LT3740EDHC#TRPBF	16-Lead DFN (5mm x 3mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys

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

Software Resources

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Hardware Ecosystem

Parts	Product Life Cycle	Description
Circuit Monitors 1
LTC2960	RECOMMENDED FOR NEW DESIGNS	36V Nano-Current Two-Input Voltage Monitor
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 1

LT3740 Demo Circuit - Wide Operating Range No Rsense Synchronous Step-Down Controller (5V to 1.8V @ 10A)

Models for the following parts are available in LTspice:

LT3740

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.