Home Power management DC/DC switching regulators Step-up (boost) regulators Boost controllers (external switch)

LM3481

ACTIVE

2.97V to 48V High-Efficiency Controller for Boost, SEPIC and Flyback

A newer version of this product is available

open-in-new Compare alternates
Same functionality with different pin-out to the compared device
LM5155 ACTIVE 2.2-MHz wide VIN, 1.5-A MOSFET driver, non-synchronous boost controller Up to 2.2-MHz Fsw, higher efficiency and up to 45-V input operating voltage.
LM5156H ACTIVE 2.2-MHz wide VIN nonsynchronous boost, flyback, & SEPIC controller with dual random spread spectrum A newer device with up to 2.2-MHz Fsw, higher efficiency, spread spectrum, up to 60-V input operating voltage, and an HTSSOP package.

Product details

Topology Boost, Flyback, Forward, SEPIC Vin (min) (V) 2.97 Vin (max) (V) 48 Vout (min) (V) 1.26 Vout (max) (V) 500 Regulated outputs (#) 1 Switching frequency (min) (kHz) 100 Switching frequency (max) (kHz) 1000 Iq (typ) (mA) 3.7 Features Adjustable current limit, Enable, Frequency synchronization, Light Load Efficiency, Nonsynchronous rectification, Pre-Bias Start-Up, UVLO adjustable Duty cycle (max) (%) 85 Rating Catalog Operating temperature range (°C) -40 to 125 Type Controller
Topology Boost, Flyback, Forward, SEPIC Vin (min) (V) 2.97 Vin (max) (V) 48 Vout (min) (V) 1.26 Vout (max) (V) 500 Regulated outputs (#) 1 Switching frequency (min) (kHz) 100 Switching frequency (max) (kHz) 1000 Iq (typ) (mA) 3.7 Features Adjustable current limit, Enable, Frequency synchronization, Light Load Efficiency, Nonsynchronous rectification, Pre-Bias Start-Up, UVLO adjustable Duty cycle (max) (%) 85 Rating Catalog Operating temperature range (°C) -40 to 125 Type Controller
VSSOP (DGS) 10 14.7 mm² 3 x 4.9
  • 10-Lead VSSOP package
  • Internal push-pull driver with 1-A peak current capability
  • Current limit and thermal shutdown
  • Frequency compensation optimized with a capacitor and a resistor
  • Internal soft start
  • Current mode operation
  • Adjustable undervoltage lockout with hysteresis
  • Pulse skipping at light loads
  • Key specifications
    • Wide supply voltage range of 2.97 V to 48 V
    • 100-kHz to 1-MHz Adjustable and synchronizable clock frequency
    • ±1.5% (over temperature) internal reference
    • 10-µA shutdown current (over temperature)
  • Create a custom design using the LM3481 with the WEBENCH Power Designer
  • 10-Lead VSSOP package
  • Internal push-pull driver with 1-A peak current capability
  • Current limit and thermal shutdown
  • Frequency compensation optimized with a capacitor and a resistor
  • Internal soft start
  • Current mode operation
  • Adjustable undervoltage lockout with hysteresis
  • Pulse skipping at light loads
  • Key specifications
    • Wide supply voltage range of 2.97 V to 48 V
    • 100-kHz to 1-MHz Adjustable and synchronizable clock frequency
    • ±1.5% (over temperature) internal reference
    • 10-µA shutdown current (over temperature)
  • Create a custom design using the LM3481 with the WEBENCH Power Designer

The LM3481 device is a versatile Low-Side N-FET high-performance controller for switching regulators. The device is designed for use in boost, SEPIC and flyback converters and topologies requiring a low-side FET as the primary switch. The LM3481 device can be operated at very high switching frequencies to reduce the overall solution size. The switching frequency of the LM3481 device can be adjusted to any value between 100 kHz and 1 MHz by using a single external resistor or by synchronizing it to an external clock. Current mode control provides superior bandwidth and transient response in addition to cycle-by-cycle current limiting. Current limit can be programmed with a single external resistor.

The LM3481 device has built-in protection features such as thermal shutdown, short-circuit protection and overvoltage protection. Power-saving shutdown mode reduces the total supply current to 5 µA and allows power supply sequencing. Internal soft start limits the inrush current at start-up. Integrated current slope compensation simplifies the design and, if needed for specific applications, can be increased using a single resistor.

The LM3481 device is a versatile Low-Side N-FET high-performance controller for switching regulators. The device is designed for use in boost, SEPIC and flyback converters and topologies requiring a low-side FET as the primary switch. The LM3481 device can be operated at very high switching frequencies to reduce the overall solution size. The switching frequency of the LM3481 device can be adjusted to any value between 100 kHz and 1 MHz by using a single external resistor or by synchronizing it to an external clock. Current mode control provides superior bandwidth and transient response in addition to cycle-by-cycle current limiting. Current limit can be programmed with a single external resistor.

The LM3481 device has built-in protection features such as thermal shutdown, short-circuit protection and overvoltage protection. Power-saving shutdown mode reduces the total supply current to 5 µA and allows power supply sequencing. Internal soft start limits the inrush current at start-up. Integrated current slope compensation simplifies the design and, if needed for specific applications, can be increased using a single resistor.

Download View video with transcript Video

Technical documentation

star =Top documentation for this product selected by TI
No results found. Please clear your search and try again.
View all 16
Type Title Date
* Data sheet LM3481High-Efficiency Controller for Boost, SEPIC and Flyback DC/DC Converters datasheet (Rev. G) PDF | HTML 10 Sep 2018
Application note AN-1286 Compensation for the LM3478 Boost Controller (Rev. D) PDF | HTML 09 Aug 2022
Application note LM34xx How to Design Flyback Converter with LM3481 Boost Controller (Rev. A) 08 Apr 2019
Selection guide Power Management Guide 2018 (Rev. R) 25 Jun 2018
Technical article Eliminating noise from the factory floor PDF | HTML 29 Sep 2016
EVM User's guide LM3481 flyback EVM User's Guide 19 May 2016
Technical article How do you generate a high voltage from a single cell Li Ion battery? PDF | HTML 11 Dec 2015
Application note Softstart Using Constant Current Constant Voltage Approach 24 Jul 2015
Technical article Portable speaker power: Making the bass possible PDF | HTML 12 May 2015
Application note Demystifying Type II and Type III Compensators Using Op-Amp and OTA for DC/DC Co 11 Jul 2014
EVM User's guide AN-1756 LM3481 Evaluation Board (Rev. A) 01 May 2013
User guide AN-2094 LM3481 SEPIC Evaluation Board (Rev. A) 25 Apr 2013
Application note AN-1484 Designing A SEPIC Converter (Rev. E) 23 Apr 2013
Application note AN-1990 Compensation for Current Mode Control SEPIC Converters (Rev. A) 23 Apr 2013
Application note Modeling & Design of Current Mode Control Boost Converters (Rev. B) 23 Apr 2013
User guide 330mW AC or DC Tiny Flyback Converter Power Supply Reference Design User Guide 27 Jan 2012

Design & development

For additional terms or required resources, click any title below to view the detail page where available.

Evaluation board

LM3481-FLYBACKEVM — Isolated Flyback Topology Evaluation Module for LM3481 Boost Controller

The Texas Instruments LM3481-FLYBACKEVM helps designers evaluate the performance of the LM3481 DC/DC Boost Controller in an isolated flyback topology. The EVM operates from an 5.5V to 36V input and provides a Isolated  12V output at 2A.
User guide: PDF
Not available on TI.com
Evaluation board

LM3481EVAL — High Efficiency Boost Switching Controller Eval Board with 12 Volt Output

The LM3481 is a current mode, low side N channel FET controller. It can be utilized in numerous configurations including a Boost, Flyback or SEPIC (Single Ended Primary Inductor Converter). This evaluation board demonstrates the flexibility of the LM3481 in a boost topology providing 12 volt output (...)

User guide: PDF
Not available on TI.com
Evaluation board

LM3481SEPICEVAL — LM3481 SEPIC Evaluation Board

The LM3481 SEPIC evaluation board is designed to provide the design engineer with a fully functional power converter solution with two output voltage options. It produces a selectable output voltage of 12 V at 1.25A or 5V at 3A. The switching frequency for the converter is set to 500 kHz. The (...)

User guide: PDF
Not available on TI.com
Simulation model

LM3481 PSpice Average Model

SNVM170.ZIP (54 KB) - PSpice Model
Simulation model

LM3481 STARTUP TINA-TI TRANSIENT REFERENCE DESIGN

SNVMBT9.TSC (140 KB) - TINA-TI Reference Design
Simulation model

LM3481 TINA-TI Average Reference Design

SNVMA06.TSC (58 KB) - TINA-TI Reference Design
Simulation model

LM3481 TINA-TI Average Spice Model

SNVMA07.ZIP (8 KB) - TINA-TI Spice Model
Simulation model

LM3481 TINA-TI Load Transient Reference Design (Rev. C)

SNVM229C.TSC (600 KB) - TINA-TI Reference Design
Simulation model

LM3481 TINA-TI Steady State Reference Design (Rev. B)

SNVM418B.TSC (600 KB) - TINA-TI Reference Design
Simulation model

LM3481 TINA-TI TRANSIENT SPICE MODEL (Rev. C)

SNVM230C.ZIP (29 KB) - TINA-TI Spice Model
Simulation model

LM3481 Unencrypted PSpice Average Model

SNVMA10.ZIP (1 KB) - PSpice Model
Simulation model

LM3481 Unencrypted PSpice Transient Model (Rev. D)

SNVM713D.ZIP (117 KB) - PSpice Model
Calculation tool

FLYBUCK-FLYBACK-DESIGN-CALC Flybuck / Flyback Calculator

This tool helps a power supply engineer to select the right isolated DC-DC topology based on the specifications. Depending on the topology chosen, the calculator also recommends the right IC for the design.

Supported products & hardware

Supported products & hardware

Products
Boost converters (integrated switch)
LM2577 3.5-V to 40-V, 3-A low component count step-up regulator LM2585 4-V to 40-V, 3-A step-up wide VIN flyback regulator LM2586 4-V to 40-V, 3-A step-up wide VIN flyback regulator with frequency synchronization LM2587 4V to 40V, 5A Step-Up Wide Vin Flyback Regulator LM2588 4-V to 40-V, 5-A step-up wide VIN flyback regulator with frequency synchronization LM2621 1.2V to 14V input voltage, 1A load current, step-up DC-DC LM2623 0.8V to 14V input voltage, 2A load current, step-up DC-DC LM2623-Q1 0.8-V to 14-V input voltage, 2-A load current, step-up DC/DC, AEC-Q100 qualified LM2735 520kHz/1.6MHz space efficient boost and SEPIC DC-DC regulator LM2735-Q1 520-kHz, 1.6-MHz space efficient boost and SEPIC DC/DC regulator, AEC-Q100 qualified LM3578A 2-V to 40-VIN switching regulators in buck, boost, terminal, depending upon the application LM5000 3.1-40V Wide Vin, 2A Current Mode Non-Synchronous Boost Regulator LM5001 3.1-75V Wide Vin, 1A Current Mode Non-Synchronous Switch Mode Regulator LM5001-Q1 3.1-V to 75-V wide VIN, 1-A current mode non-synchronous switch mode regulator LM5002 3.1-75V Wide Vin, 0.5A Current Mode Boost, Flyback, Sepic Converter LM78S40 1.5A Adjustable Step Up, Step Down or Inverting Regulator TPS55340 5-A, 40-V, wide VIN boost, flyback, & SEPIC converter TPS55340-EP Enhanced integrated, 5-A, 40-V wide input range boost/SEPIC/flyback DC/DC regulator TPS55340-Q1 Integrated, 5-A 40-V wide input range boost/SEPIC/flyback DC/DC regulator, AEC-Q100 qualified TPS61175 3-A ,40V High Voltage Boost Converter with Soft-start and Programmable Switching Frequency TPS61175-Q1 3-A, 40-V high voltage boost converter with soft-start and programmable switching frequency
Buck converters (integrated switch)
LM5015 4.25-75V, Monolithic Two-Switch Forward DC-DC Regulator
Isolated DC/DC converters & modules
LM25017 7.5-48V Wide Vin, 650mA Constant On-Time Synchronous Buck Regulator LM25018 7.5-48V Wide Vin, 300mA Constant On-Time Synchronous Buck Regulator LM25019 7.5-48V Wide Vin, 100mA Constant On-Time Synchronous Buck Regulator LM34925 7.5-100V Wide Vin, 100mA Integrated Secondary Bias Regulator for Isolated DC/DC Converters LM34926 7.5-100V Wide Vin, 300mA Integrated Secondary Bias Regulator for Isolated DC/DC Converters LM34927 7.5-100V Wide Vin, 600mA Integrated Secondary Bias Regulator for Isolated DC/DC Converters LM5017 7.5-100V Wide Vin, 600mA Constant On-Time Synchronous Buck Regulator LM5018 7.5-100V Wide Vin, 300mA Constant On-Time Synchronous Buck Regulator LM5019 7.5-100V Wide Vin, 100mA Constant On-Time Synchronous Buck Regulator LM5160 LM5160 wide input 65V, 2A synchronous buck/Fly-Buck™ converter LM5160-Q1 Wide Input 65V, 2A Synchronous Buck / Fly-Buck™ Converter LM5160A LM5160A Wide Input 65V, 2A Synchronous Buck / Fly-Buck™ Converter LM5161 Wide Input 4.5-V to 100-V, 1-A Synchronous Buck / Fly-Buck Converter TPS55010 2.95V To 6V Input, 2W, Isolated DC/DC Converter with Integrated FETS
Boost controllers (external switch)
LM3017 High Efficiency Low-Side Controller with True Shutdown LM3478 2.97~40V Wide Input Range Boost/SEPIC/Flyback DC-DC Controller LM3478Q-Q1 40-V wide VIN low-side N-channel controller for switching regulators with 10-µA shutdown current LM3481 2.97V to 48V High-Efficiency Controller for Boost, SEPIC and Flyback LM3481-Q1 2.97-V to 48-V high-efficiency controller for boost, SEPIC and flyback, AEC-Q100 qualified LM3488 2.97V to 40V Wide Vin Low-Side N-Channel Controller for Switching Regulators LM3488Q-Q1 40-V wide VIN low-side N-channel controller for switching regulators with 5-µA shutdown current LM5020 13-100V Wide Vin, Current Mode PWM Boost, Flyback, Sepic Controller LM5022 6-60V Wide Vin, current mode boost, SEPIC and Flyback controller TL1451 Dual Pulse-Width-Modulation Control Circuit TL1451A 3.6V to 50V dual channel controller with Wide input voltage range TL1451A-EP Enhanced Product Dual Pulse-Width-Modulation Control Circuits TL1451A-Q1 3.6-V to 50-V dual-channel PWM controller, AEC-Q100 qualified TL5001 PWM Controller with wide input range, with ±5% tolerance on reference, operation –20°C to 85°C TL5001A PWM Controller with wide input range, with ±3% tolerance on reference, operation –20°C to 85°C TL5001A-Q1 PWM Controller with wide input range, with ±3% tolerance on reference, operation –20°C to 85°C TL5001M PWM Controller with wide input range, with ±5% tolerance on reference, operation –55°C to 125°C TPS40210-Q1 4.5-V to 52-V wide input range current mode boost controller with 700-mV reference voltage TPS40211-Q1 4.5-V to 52-V wide input range current mode boost controller with 260-mV reference voltage TPS43000 Multi-Topology (buck, boost, sepic) High Frequency DC/DC Controller UC2572 Negative output Flyback pulse width modulator
PWM controllers
LM3524D 40V, 0.2A 350KHz PWM controller
Simulation tool

PSPICE-FOR-TI — PSpice® for TI design and simulation tool

PSpice® for TI is a design and simulation environment that helps evaluate functionality of analog circuits. This full-featured, design and simulation suite uses an analog analysis engine from Cadence®. Available at no cost, PSpice for TI includes one of the largest model libraries in the (...)

Many TI reference designs include the LM3481

Use our reference design selection tool to review and identify designs that best match your application and parameters.

Package Pins Download
VSSOP (DGS) 10 View options

Ordering & quality

Information included:
  • RoHS
  • REACH
  • Device marking
  • Lead finish/Ball material
  • MSL rating/Peak reflow
  • MTBF/FIT estimates
  • Material content
  • Qualification summary
  • Ongoing reliability monitoring
Information included:
  • Fab location
  • Assembly location

Recommended products may have parameters, evaluation modules or reference designs related to this TI product.

Support & training

TI E2E™ forums with technical support from TI engineers

Content is provided "as is" by TI and community contributors and does not constitute TI specifications. See terms of use.

If you have questions about quality, packaging or ordering TI products, see TI support. ​​​​​​​​​​​​​​

Videos