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LM3481-Q1

ACTIVE

2.97-V to 48-V high-efficiency controller for boost, SEPIC and flyback, AEC-Q100 qualified

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Data sheet

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Same functionality with different pin-out to the compared device
LM5155-Q1 ACTIVE 2.2-MHz wide VIN, 1.5-A MOSFET driver, non-synchronous boost controller, AEC-Q100 qualified Up to 2.2-MHz Fsw, higher efficiency and up to 45-V input operating voltage.
LM5156-Q1 ACTIVE 2.2-MHz wide VIN nonsynchronous boost, flyback, & SEPIC controller with dual random spread spectrum Up to 2.2-MHz Fsw, higher efficiency, spread spectrum and up to 60-V input operating voltage.
Similar functionality to the compared device
TPS40210-Q1 ACTIVE 4.5-V to 52-V wide input range current mode boost controller with 700-mV reference voltage For applications requiring lower quiescent current or higher efficiency.

LM3481-Q1

ACTIVE
Data sheet Order now

Product details

Rating Automotive Topology Boost, Flyback, Forward, SEPIC Vin (max) (V) 48 Vin (min) (V) 2.97 Vout (max) (V) 500 Vout (min) (V) 1.26 Control mode current mode Features Adjustable current limit, Enable, Frequency synchronization, Light load efficiency, Nonsynchronous rectification, Prebias startup, UVLO adjustable Operating temperature range (°C) -40 to 125 Iq (typ) (µA) 3700 Duty cycle (max) (%) 85
Rating Automotive Topology Boost, Flyback, Forward, SEPIC Vin (max) (V) 48 Vin (min) (V) 2.97 Vout (max) (V) 500 Vout (min) (V) 1.26 Control mode current mode Features Adjustable current limit, Enable, Frequency synchronization, Light load efficiency, Nonsynchronous rectification, Prebias startup, UVLO adjustable Operating temperature range (°C) -40 to 125 Iq (typ) (µA) 3700 Duty cycle (max) (%) 85
VSSOP (DGS) 10 14.7 mm² 3 x 4.9
  • AEC-Q100 Qualified for automotive applications:
    • Device temperature grade 1: -40°C to +125°C, TA
  • 10-Lead VSSOP package
  • Internal push-pull driver with 1A 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 2.97V to 48V
    • 100kHz to 1MHz Adjustable and synchronizable clock frequency
    • ±1.5% (over temperature) internal reference
    • 10µA shutdown current (over temperature)
  • Create a custom design using the LM3481-Q1 with the WEBENCH Power Designer
  • AEC-Q100 Qualified for automotive applications:
    • Device temperature grade 1: -40°C to +125°C, TA
  • 10-Lead VSSOP package
  • Internal push-pull driver with 1A 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 2.97V to 48V
    • 100kHz to 1MHz Adjustable and synchronizable clock frequency
    • ±1.5% (over temperature) internal reference
    • 10µA shutdown current (over temperature)
  • Create a custom design using the LM3481-Q1 with the WEBENCH Power Designer

The LM3481-Q1 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-Q1 device can be operated at very high switching frequencies to reduce the overall solution size. The switching frequency of the LM3481-Q1 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-Q1 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-Q1 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-Q1 device can be operated at very high switching frequencies to reduce the overall solution size. The switching frequency of the LM3481-Q1 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-Q1 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.
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Technical documentation

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Type Title Date
* Data sheet LM3481-Q1 High-Efficiency Controller for Boost, SEPIC and Flyback DC/DC Converters datasheet (Rev. B) PDF | HTML 09 Dec 2024
Application brief Avoiding Pulse Skip Operation at Light Load Conditions for Asynchronous Boost Converter Designs PDF | HTML 16 Sep 2025
Technical article Create a 24W power supply for automotive LED lighting systems PDF | HTML 14 Oct 2016
User guide AN-2094 LM3481 SEPIC Evaluation Board (Rev. A) 25 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
Simulation model

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

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

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

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

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

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

LM3481 Unencrypted PSpice Transient Model (Rev. D)

SNVM713D.ZIP (117 KB) - PSpice Model
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CAD/CAE symbol

330mW AC or DC Tiny Flyback Converter Power Supply Reference Design CAD File

SNVC023.ZIP (733 KB)
Download
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
AC/DC & DC/DC controllers (external FET)
  • 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
  • LM3524D — 40V, 0.2A 350KHz PWM controller
  • LM3578A — 2-V to 40-VIN switching regulators in buck, boost, terminal, depending upon the application
  • 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
  • TPS55010 — 2.95V To 6V Input, 2W, Isolated DC/DC Converter with Integrated FETS
  • UC2572 — Negative output Flyback pulse width modulator
AC/DC & DC/DC converters (integrated FET)
  • 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
  • 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
  • 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
  • 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
  • LM5015 — 4.25-75V, Monolithic Two-Switch Forward DC-DC Regulator
  • 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
  • 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
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Calculation tool

LM3481-BOOST-CALC — LM3481 Quickstart Calculator for Boost

The LM3481 Boost Quickstart Calculator Tool assist in the configuration of the power stage and the external components for the LM3481.
Supported products & hardware

Supported products & hardware

Products
AC/DC & DC/DC controllers (external FET)
  • 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
Hardware development
Evaluation board
  • LM3481-FLYBACKEVM — Isolated Flyback Topology Evaluation Module for LM3481 Boost Controller
  • LM3481EVAL — High Efficiency Boost Switching Controller Eval Board with 12 Volt Output
Download
Calculation tool

LM3481-FLYBACK-CALC — LM3481 quick start calculator for Flyback

The LM3481 Flyback quick start calculator tool assist in the configuration of the power stage and the external components for the LM3481
Supported products & hardware

Supported products & hardware

Products
AC/DC & DC/DC controllers (external FET)
  • 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
Hardware development
Evaluation board
  • LM3481-FLYBACKEVM — Isolated Flyback Topology Evaluation Module for LM3481 Boost Controller
  • LM3481EVAL — High Efficiency Boost Switching Controller Eval Board with 12 Volt Output
Download
Calculation tool

LM3481-SEPIC-CALC — LM3481 quick start calculator for SEPIC

The LM3481 SEPIC quick start calculator tool assists in the configuration of the power stage and the external components for the LM3481 device.
Supported products & hardware

Supported products & hardware

Products
AC/DC & DC/DC controllers (external FET)
  • 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
Hardware development
Evaluation board
  • LM3481-FLYBACKEVM — Isolated Flyback Topology Evaluation Module for LM3481 Boost Controller
  • LM3481EVAL — High Efficiency Boost Switching Controller Eval Board with 12 Volt Output
Download
Reference designs

TIDA-01234 — 24W Boost and Boost-to-Battery Reference Design for Automotive LED Lighting

TIDA-01234 is a 24W, high-efficiency (94%), low cost, Asynchronous boost design for automotive LED application based on LM3481-Q1.
This design applies to automotive high brightness lighting such as headlights and taillights and also interior LED lighting systems. It is designed to operate with an (...)
Design guide: PDF
Schematic: PDF
Reference designs

PMP22589 — Ultrawide input, 10-W isolated flyback reference design

This reference design is a wide-Vin, low-power flyback design that can take dual inputs from 19 VDC to 60 VDC and 85 VAC to 275 VAC. It is designed to provide 24 V at 420 mA to the output load.
Test report: PDF
Reference designs

PMP21404 — High efficiency boost converter power supply reference design for automotive DC/AC inverter

This single-phase boost converter operates over an input voltage range of 120 V - 350 V and provides a non-isolated output of 221 V / 0.87 A. Input voltages above 221 V are passed through to the output. With an efficiency of greater than 97%, component losses are reduced, which results in lowers (...)
Test report: PDF
Schematic: PDF
Reference designs

PMP40100 — Isolated Multi-rail Output Flyback Reference Designs for HEV/EV Battery Management Systems

The PMP40100 is an isolated flyback solution which accepts an input voltage of 5V to 36V and provides multiple 3KV isolated output rails to the load. The reference design is set up for 15V at 100mA, and 6V rails at 300mA each. The reference design features good line and load regulation and good (...)
Test report: PDF
Schematic: PDF
Reference designs

TIDA-00744 — 50W System-Level Power Reference Design for Automotive Infotainment Systems

TIDA-00744 is a 50-W system-level SMPS design for mid-power automotive infotainment systems.
The design has protections, such as load dump through TVS (ISO pulse testing), as well as reverse voltage (innovative smart diode with very low Iq) protection. Furthermore, all the controllers (boost and (...)
Design guide: PDF
Schematic: PDF
Reference designs

LM3481-REF — 330mW AC or DC Tiny Flyback Converter Power Supply Reference Design

The main purpose of the power supply is to convert the rectified AC Input to DC regulated current for 6 LEDs.  The power supply provides protection for the LEDs, limits the transient input voltage and protect against inrush current at plug in.  The overall power supply conformity (e.g. (...)
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