LTC3408

PRODUCTION

1.5MHz, 600mA Synchronous Step-Down Regulator with Bypass Transistor

Part Models: 2
1ku List Price: Starting From $2.62

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Overview

Dynamically Adjustable Output from 0.3V to 3.5V
600mA Output Current
Internal 0.08Ω P-Channel MOSFET Bypass Transistor
High Efficiency: Up to 96%
1.5MHz Constant Frequency Operation
No Schottky Diode Required
Low Dropout Operation: 100% Duty Cycle
2.5V to 5V Input Voltage Range
Shutdown Mode Draws <1µA Supply Current
Current Mode Operation for Excellent Line and Load Transient Response
Overtemperature Protected
Available in 8-Lead 3mm x 3mm DFN Package

The LTC3408 is a high efficiency monolithic synchronous buck regulator optimized for WCDMA power amplifier applications. The output voltage can be dynamically programmed from 0.3V to 3.5V. At V_OUT > 3.6V an internal 0.08Ω bypass P-channel MOSFET connects V_OUT directly to V_IN, eliminating power loss through the inductor.

The input voltage range is 2.5V to 5V making the LTC3408 ideally suited for single Li-Ion battery-powered applications. 100% duty cycle provides low dropout operation, extending battery life in portable systems.

Switching frequency is internally set at 1.5MHz, allowing the use of small surface mount inductors and capacitors. The internal synchronous switch increases efficiency and eliminates the need for an external Schottky diode.

The LTC3408 is available in a low profile (0.75mm) 8-lead 3mm × 3mm DFN package.

Applications

WCDMA Cell Phone Power Amplifiers
Wireless Modems

Part Models: 2
1ku List Price: Starting From $2.62

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
LTC3408EDD#PBF	8-Lead DFN (3mm x 3mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LTC3408EDD#TRPBF	8-Lead DFN (3mm x 3mm x 0.75mm 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
Power System Management (PSM) & Sequencers 1
LTC2974	RECOMMENDED FOR NEW DESIGNS	4-Channel PMBus Power System Manager Featuring Accurate Output Current Measurement
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

Models for the following parts are available in LTspice:

LTC3408

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.