LT3120

RECOMMENDED FOR NEW DESIGNS

LT3120

26V, 9A Low-I_Q CC/CV Monolithic Buck-Boost Converter

RECOMMENDED FOR NEW DESIGNS

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1ku List Price Starting From $4.07

Features

Input Voltage Range: 2.5V to 26V
0.8V to 24V Output Voltage Range
High Output Current
- 6.5A with V_OUT = 5V, V_IN > 6V
- 3A with V_OUT = 5V, V_IN = 3V
- 6.5A with V_OUT = 12V, V_IN > 14V
- 4 A with V_OUT = 12V, V_IN = 9V
Ultralow Noise Buck-Boost Architecture
Programmable Output Current Limit

Programmable Frequency Range: 400kHz to 2MHz
Accurate Enable Comparator Threshold
Burst Mode^® Operation, No-Load I_Q = 35μA
Current Mode Control
External Clock Synchronization
Maximum Power Point Control
28-Lead 4mm × 5mm LQFN Package

Additional Details

The LT3120 is a high efficiency 26V monolithic buck-boost converter. Extensive feature integration and very low resistance internal power switches minimize the total solution footprint for even the most demanding applications. A proprietary 4-switch PWM architecture provides seamless low noise operation from input voltages above, equal to, or below the output voltage.

External frequency programming as well as synchronization using an internal PLL enable operation over a wide switching frequency range of 400kHz to 2MHz. The wide 2.5V to 26V input range is well suited for operation from unregulated power sources including battery stacks and backup capacitors. After start-up, operation is possible with input voltages as low as 500mV.

Other features include, output short-circuit protection, thermal overload protection, less than 3μA shutdown current, power good indicator, Burst Mode operation, and maximum power point control.

The LT3120 is offered in thermally enhanced 28-lead 4mm × 5mm LQFN package.

APPLICATIONS

RF Power Supply
USB Power Delivery
System Backup Power Supply
1-Cell to 5-Cell Lithium Battery Powered Products
Wide Input Range Power Supply
Lead Acid to 12V Regulator

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Submit your question below and we will return the best answer from ADI’s knowledge database:

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Analog Devices Support Portal is a one-stop shop to answer all your ADI questions.

Visit the ADI Support Page

Ask the ADI community for help.

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FAQs

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Part Models 1

1ku List Price Starting From $4.07

Technical Documents 2

LT3120: 26V, 9A Low-I_Q CC/CV Monolithic Buck-Boost Converter Data Sheet (Rev.0) 05/04/2021

DC2815A Demo Manual (Rev.0) 06/18/2021

Design Resources 1

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
LT3120JV#PBF	28-Lead LQFN (5mm x 4mm x 0.74mm)	HTML Material Declaration HTML Reliablity Data	Ultra Librarian SamacSys

LT3120JV#PBF
Pin/Package Drawing
28-Lead LQFN (5mm x 4mm x 0.74mm)
Documentation

HTML Material Declaration

HTML Reliablity Data

CAD Symbols, Footprints, and 3D Models
Ultra Librarian
SamacSys

DC2815A

LT3120 | 26V, 9A Synchronous Buck-Boost DC/DC Converter with Accurate Programmable Output Current Limit

Test Procedure Setup Drawing for DC2815A

LT3120 | 26V, 9A Synchronous Buck-Boost DC/DC Converter with Accurate Programmable Output Current Limit

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DC2815A

LT3120 | 26V, 9A Synchronous Buck-Boost DC/DC Converter with Accurate Programmable Output Current Limit

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Product Detail

Demonstration circuit 2815A features the LT3120, as wide operating range synchronous monolithic buck-boost converter with programmable output current limit.

The DC2815A demo board has four user selectable operating modes:

An accurate programmable EN/UVLO pin which is used to ENABLE the converter (JP1).
Programmable MPPC (Maximum Power Point Control) for Input Regulation Set Point (JP2).
Burst Mode^® operation and External CLK/Fixed Frequency PWM (JP3).
Programmable Output Average Current Limit Set Point (JP4).

The LT3120 uses average current mode control to simplify voltage loop compensation and provide good line and load transient response.

The DC2815A operates with a 2.5V to 26V input voltage range. The demo board has been designed with the output voltage set to 5V. The LT3120 incorporates a proprietary low noise switching algorithm which optimizes efficiency with input voltages above, below or equal to the output voltage and ensures seamless transitions between operating modes.

In PWM mode, the switching frequency can operate between 400kHz to 2MHz by programming the RT resistor R5. LT3120 can be synchronized to an External CLK provided RT is programmed 25% to 50% below the synchronization frequency.

The LT3120 has an optional programmable current limit that can be used to control the output current. The current limit circuit requires an external sense resistor connected between ISP and ISN and the current limit value can be set by adjusting R6 and C26 connected to PROG pin.

LT3120 also has programmable MPPC feature to set the input regulation voltage and can be adjusted by changing R13, R14 and C28.

The LT3120 data sheet has detailed information about the operation, specifications, and applications of the part. The data sheet should be read in conjunction with the DC2815A quick start guide.

Resources

ZIP

DC2815A - Design Files

308.32 K

PDF

DC2815A Demo Manual (Rev.0)

552.31 K

PDF

DC2815A - Schematic

100.69 K

DC2815A

LT3120 | 26V, 9A Synchronous Buck-Boost DC/DC Converter with Accurate Programmable Output Current Limit

LTspice 1

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.

To launch ready-to-run LTspice demonstration circuits for this part:

Step 1: Download and install LTspice on your computer.

Step 2: Click on the link in the section below to download a demonstration circuit.

Step 3: If LTspice does not automatically open after clicking the link below, you can instead run the simulation by right clicking on the link and selecting “Save Target As.” After saving the file to your computer, start LTspice and open the demonstration circuit by selecting ‘Open’ from the ‘File’ menu.