4-A, 50-V, 2.2-MHz wide VIN boost, flyback, & SEPIC converter with dual random spread spectrum


Product details


Vin (Min) (V) 1.5 Vin (Max) (V) 45 Vout (Min) (V) 1.5 Vout (Max) (V) 48 Switch current limit (Typ) (A) 5 Regulated outputs (#) 1 Switching frequency (Min) (kHz) 100 Switching frequency (Max) (kHz) 2200 Iq (Typ) (mA) 0.67 Features Enable, Frequency Synchronization, Light Load Efficiency, Power Good, Spread Spectrum, UVLO Adjustable Duty cycle (Max) (%) 93 Operating temperature range (C) -40 to 150 Rating Automotive open-in-new Find other Boost converters (integrated switch)

Package | Pins | Size

WQFN (RTE) 16 9 mm² 3 x 3 open-in-new Find other Boost converters (integrated switch)


  • AEC-Q100 qualified for automotive applications
    • Temperature grade 1: –40°C to +125°C TA
  • Functional Safety-Capable
  • Suited for wide operating range for car battery applications
    • 2.9-V to 45-V input operating range
    • 48-V maximum output (50-V abs max)
    • Minimum boost supply voltage of 1.5 V when BIAS ≥ 2.9 V
    • Input transient protection up to 50 V
    • Minimized battery drain
      • Low shutdown current (IQ ≤ 2.6 µA)
      • Low operating current (IQ ≤ 700 µA)
  • Small solution size and low cost
    • Maximum switching frequency up to 2.2 MHz
    • 16-pin QFN package (3 mm × 3 mm) with wettable flanks
    • Integrated error amplifier allows primary-side regulation without optocoupler (flyback)
    • Minimized undershoot during cranking (start-stop application)
    • Accurate current limit (see the Device Comparison Table)
  • EMI mitigation
    • Selectable dual random spread spectrum
    • Lead-less package
  • Higher efficiency with low-power dissipation
    • 45-mΩ RDSON switch
    • Fast switching, small switching loss
  • Avoid AM band interference and crosstalk
    • Optional clock synchronization
    • Dynamically programmable wide switching frequency from 100 kHz to 2.2 MHz
  • Integrated protection features
    • Constant current limiting over input voltage
    • Selectable hiccup mode overload protection
    • Programmable line UVLO
    • OVP protection
    • Thermal shutdown
  • Accurate ±1% accuracy feedback reference
  • Adjustable soft start
  • PGOOD indicator
  • Create a custom design using the LM5157x-Q1 with the WEBENCH Power Designer
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The LM5157x-Q1 device is a wide input range, non-synchronous boost converter with integrated 50-V, 6.5-A (LM5157-Q1) or 50-V, 4.33-A (LM51571-Q1) power switch.

The device can be used in boost, SEPIC, and flyback topologies. The device can start up from a single-cell battery with a minimum of 2.9 V. It can operate with the input supply voltage as low as 1.5 V if the BIAS pin is greater than 2.9 V.

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Technical documentation

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Type Title Date
* Data sheet LM5157x-Q1 2.2-MHz Wide VIN 50-V Boost/SEPIC/Flyback Converter with Dual Random Spread Spectrum datasheet (Rev. A) Mar. 02, 2021
User guide LM5157-Q1 Flyback Converter Evaluation Module May 04, 2021
Technical article Lowering audible noise in automotive applications with TI’s DRSS technology Mar. 18, 2021
Analog design journal The pros and cons of spread‐spectrum implementation methods in buck regulators Mar. 18, 2021
Functional safety information LM5157x-Q1 Functional Safety, FIT Rate, Failure Mode Distribution Mar. 01, 2021
Application note EMI Reduction Technique, Dual Random Spread Spectrum Jun. 19, 2020

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 LM5157EVM-BST evaluation module showcases the features and performance of the LM5157 device as wide input voltage, boost converter with dual random spread spectrum. The standard configuration is designed to provide a regulated output of 12V at 1.6A from an input of 3V to 9V (load derated by half (...)
  • Input voltage range: 3V to 9V
  • Isolated output voltage 12V at 1.6A (load derated by half from < 6V input)
  • Switching frequency 2.1MHz
  • Dual random spread spectrum
document-generic User guide
The LM5157EVM-FLY evaluation module showcases the features and performance of the LM5157 as a flyback converter to produce multiple output voltage rails for typical applications of the 3phase inverter gate driver bias supplies.  The standard configuration is designed to provide a regulated (...)
  • Input voltage range:  8 V to 16 V
  • Main output:  10 V, 250 mA
  • Isolated output 1: 20 V, 75 mA
  • Isolated output 2: 20 V, 75 mA
  • Isolated output 3: 20 V, 150 mA
  • Switching frequency:  250 kHz

Design tools & simulation

SNVMC63.ZIP (53 KB) - PSpice Model
SNVMC64.ZIP (193 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
  • (...)

CAD/CAE symbols

Package Pins Download
WQFN (RTE) 16 View options

Ordering & quality

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  • Ongoing reliability monitoring

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