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


Product details


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, Pre-Bias Start-Up, UVLO Adjustable Duty cycle (Max) (%) 85 Rating Automotive Operating temperature range (C) -40 to 125 open-in-new Find other Boost controllers (external switch)

Package | Pins | Size

VSSOP (DGS) 10 9 mm² 3 x 3 open-in-new Find other Boost controllers (external switch)


  • LM3481QMM are Automotive-Grade Products
    That are AEC-Q100 Grade 1 Qualified (–40°C to
    +125°C Operating Junction Temperature)
  • 10-Lead VSSOP Package
  • Internal Push-Pull Driver With 1-A Peak Current
  • Current Limit and Thermal Shutdown
  • Frequency Compensation Optimized With a Capacitor
    and a Resistor
  • Internal Softstart
  • 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
    • 10-µA Shutdown Current (Over Temperature)
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The LM3481 device is a versatile Low-Side N-FET high-performance controller for switching regulators. The device is suitable for use in topologies requiring a low-side FET, such as boost, flyback, SEPIC, and so on. The LM3481 device can be operated at extremely high switching frequencies to reduce the overall solution size. The switching frequency of the LM3481 device can be adjusted to any value between 100kHz and 1MHz 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.

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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. F) Nov. 05, 2012
Technical article How to add overvoltage protection to a synchronous boost controller Sep. 17, 2018
Technical article Create a 24W power supply for automotive LED lighting systems Oct. 14, 2016
User guide AN-1756 LM3481 Evaluation Board (Rev. A) May 01, 2013
User guide AN-2094 LM3481 SEPIC Evaluation Board (Rev. A) Apr. 25, 2013
User guide 330mW AC or DC Tiny Flyback Converter Power Supply Reference Design User Guide Jan. 27, 2012

Design & development

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

Hardware development

document-generic User guide

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 (...)

document-generic User guide

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 (...)


5V Output Voltage Option:

  • Input Voltage Range : 4.5V to 25V
  • Output Voltage : 5V ± 2%
  • Output Current : 0A to 3A
  • Switching Frequency : 500 kHz
  • Load Regulation : 0.1%
  • Board Size : 2.4 x 1.8 inches

12V Output Voltage Option:

  • Input Voltage Range : 4.5V to 18V
  • Output Voltage : 12V ± 2%
  • Output Current : 0A to 1.25A
  • (...)

Design tools & simulation

SNVM229C.TSC (600 KB) - TINA-TI Reference Design
SNVM230C.ZIP (29 KB) - TINA-TI Spice Model
SNVM418B.TSC (600 KB) - TINA-TI Reference Design
SNVM713D.ZIP (117 KB) - PSpice Model
PSpice® for TI design and simulation tool
PSPICE-FOR-TI — 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 (...)
  • Leverages Cadence PSpice Technology
  • Preinstalled library with a suite of digital models to enable worst-case timing analysis
  • Dynamic updates ensure you have access to most current device models
  • Optimized for simulation speed without loss of accuracy
  • Supports simultaneous analysis of multiple products
  • (...)
Fly-Buck and Flyback Topology Selector
FLYBUCK-FLYBACK-DESIGN-CALC 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.
  • Features isolated topologies like Fly-Buck™, Fly-Buck-Boost, DCM and CCM Flyback
  • Capability to design up to 6 isolated outputs
  • Recommends ICs for desired application design
  • Incorporates loop compensation in designs
  • Compares efficiency, external component count and transformer currents for every topology (...)
SNVC023.ZIP (733 KB)

Reference designs

Many TI reference designs include the LM3481-Q1 Use our reference design selection tool to review and identify designs that best match your application and parameters.

CAD/CAE symbols

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VSSOP (DGS) 10 View options

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