LTC3121

RECOMMENDED FOR NEW DESIGNS

15V, 1.5A Synchronous Step-Up DC/DC Converter with Output Disconnect

Part Models: 4
1ku List Price: Starting From $2.81

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Overview

V_IN Range: 1.8V to 5.5V, 500mV After Start-Up
Output Voltage Range: 2.2V to 15V
400mA Output Current for V_IN = 5V and V_OUT = 12V
Output Disconnects from Input When Shut Down
Synchronous Rectification: Up to 95% Efficiency
Inrush Current Limit
Up to 3MHz Adjustable Switching Frequency Synchronizable to External Clock
Selectable Burst Mode^® Operation: 25μA I_Q
Output Overvoltage Protection
Soft-Start
<1μA I_Q in Shutdown
12-Lead, 3mm × 4mm Thermally Enhanced DFN Package

The LTC3121 is a synchronous step-up DC/DC converter with true output disconnect and inrush current limiting. The 1.5A current limit along with the ability to program output voltages up to 15V makes the LTC3121 well suited for a variety of demanding applications. Once started, operation will continue with inputs down to 500mV, extending run time in many applications.

The LTC3121 features output disconnect in shutdown, dramatically reducing input power drain and enabling V_OUT to completely discharge. Adjustable PWM switching from 100kHz to 3MHz optimizes applications for highest efficiency or smallest solution footprint. The oscillator can also be synchronized to an external clock for noise sensitive applications. Selectable Burst Mode operation reduces quiescent current to 25μA, ensuring high efficiency across the entire load range. An internal soft-start limits inrush current during start-up.

Other features include a <1μA shutdown current and robust protection under short-circuit, thermal overload, and output overvoltage conditions. The LTC3121 is offered in a low profile 12-lead (3mm × 4mm × 0.75mm) DFN package.

Applications

PCI Express Cards/Systems
Piezo Actuators
Small DC Motors
12V Analog Rail From Battery, 5V, or Backup Capacitor

Part Models: 4
1ku List Price: Starting From $2.81

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
LTC3121EDE#PBF	12-Lead DFN (4mm x 3mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LTC3121EDE#TRPBF	12-Lead DFN (4mm x 3mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LTC3121IDE#PBF	12-Lead DFN (4mm x 3mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LTC3121IDE#TRPBF	12-Lead DFN (4mm 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
Protection Switches & Controllers 1
LTC4417	RECOMMENDED FOR NEW DESIGNS	Prioritized PowerPath^™ Controller

Parts	Product Life Cycle	Description
LTC3122	RECOMMENDED FOR NEW DESIGNS	15V, 2.5A Synchronous Step-Up DC/DC Converter with Output Disconnect

Tools & Simulations

LTspice 1

LTC3121 Demo Circuit - 5V to 12V Synchronous Boost Converter with Output Disconnect (1.8-5.5V to 12V @ 400mA)

Models for the following parts are available in LTspice:

LTC3121

LTpowerCAD 1

LTC3121 Project - 15V, 1.5A Synchronous Step-Up DC/DC Converter with Output Disconnect (1.8-5.5V to 12V @ 400mA)

Design tools for the following parts are available in LTpowerCAD:

LTC3121

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.

LTpowerCAD^® is a power supply design program which selects power stage components, provides detailed power efficiency, shows quick loop Bode plot stability and load transient analysis, and can export to LTspice for simulation.

Evaluation Kits

LTC3121EDE Demo Board | Synchronous Boost, 1.8V ≤ VIN ≤ 5.5V, VOUT = 12V @ up to 400mA

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Product Details

Demonstration circuit 2372A is a 5.5V input, 12V output at 400mA DC/DC power supply featuring the LTC3121. The IC includes internal high and low side 1.5A switches and features selectable PWM or Burst Mode^® operation for high efficiency at low output current. The board operates from an input voltage as low as 1.8V and continues to operate down to 500mV once started. The output is fixed at 12V although other voltages between 2.2V and 15V can be selected by resistor changes.

Resources

DC2372A - Design Files
9/30/2015

DC2372A - Schematic
9/30/2015

DC2372A - Demo Manual
9/30/2015

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