LM5157

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6A/4A, 50-V, 2.2-MHz wide VIN boost, flyback, & SEPIC converter with dual random spread spectrum

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Data sheet

document-pdfAcrobat LM5157 2.2-MHz Wide VIN 50-V Boost/SEPIC/Flyback Converter with Dual Random Spread Spectrum datasheet (Rev. A) PDF | HTML

LM5157

ACTIVE

Data sheet

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Product details

Rating

Catalog

Topology

Boost, Flyback, SEPIC

Vin (max) (V)

45

Vin (min) (V)

1.5

Vout (max) (V)

48

Vout (min) (V)

1.5

Switch current limit (typ) (A)

7.5

Features

Enable, Frequency synchronization, Nonsynchronous rectification, Power good, Spread Spectrum, UVLO adjustable

EMI features

Frequency Dithering, Spread Spectrum

Control mode

current mode

Operating temperature range (°C)

-40 to 125

Iq (typ) (A)

0.00067

Duty cycle (max) (%)

93

TI functional safety category

Functional Safety-Capable

Rating

Catalog

Topology

Boost, Flyback, SEPIC

Vin (max) (V)

45

Vin (min) (V)

1.5

Vout (max) (V)

48

Vout (min) (V)

1.5

Switch current limit (typ) (A)

7.5

Features

Enable, Frequency synchronization, Nonsynchronous rectification, Power good, Spread Spectrum, UVLO adjustable

EMI features

Frequency Dithering, Spread Spectrum

Control mode

current mode

Operating temperature range (°C)

-40 to 125

Iq (typ) (A)

0.00067

Duty cycle (max) (%)

93

TI functional safety category

Functional Safety-Capable

WQFN (RTE)

16

9 mm² (3 mm × 3 mm)

Suited for wide operating range for 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 (I Q ≤ 2.6 µA)
  - Low operating current (I Q ≤ 670 µA)
Small solution size and low cost
- Maximum switching frequency up to 2.2 MHz
- 16-pin QFN package (3 mm × 3 mm)
- Integrated error amplifier allows primary-side regulation without optocoupler (flyback)
- 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 R DSON 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 with the WEBENCH Power Designer

Suited for wide operating range for 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 (I Q ≤ 2.6 µA)
  - Low operating current (I Q ≤ 670 µA)
Small solution size and low cost
- Maximum switching frequency up to 2.2 MHz
- 16-pin QFN package (3 mm × 3 mm)
- Integrated error amplifier allows primary-side regulation without optocoupler (flyback)
- 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 R DSON 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 with the WEBENCH Power Designer

The LM5157 device is a wide input range, non-synchronous boost converter with integrated 50-V 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 an input supply voltage as low as 1.5 V if the BIAS pin is greater than 2.9 V.

The BIAS pin operates up to 45 V (50-V absolute maximum). The switching frequency is dynamically programmable with an external resistor from 100 kHz to 2.2 MHz. Switching at 2.2 MHz minimizes AM band interference and allows for a small solution size and fast transient response. To reduce the EMI of the power supply, the device provides a selectable Dual Random Spread Spectrum, which reduces the EMI over a wide frequency range.

The device features an accurate peak current limit over the input voltage, which avoids overdesigning power inductor. Low operating current and pulse-skipping operation improve efficiency at light loads.

The device has built-in protection features such as overvoltage protection, line UVLO, thermal shutdown, and selectable Hiccup mode overload protection. Additional features include low shutdown I Q, programmable soft start, precision reference, a power-good indicator, and external clock synchronization.

The LM5157 device is a wide input range, non-synchronous boost converter with integrated 50-V 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 an input supply voltage as low as 1.5 V if the BIAS pin is greater than 2.9 V.

The BIAS pin operates up to 45 V (50-V absolute maximum). The switching frequency is dynamically programmable with an external resistor from 100 kHz to 2.2 MHz. Switching at 2.2 MHz minimizes AM band interference and allows for a small solution size and fast transient response. To reduce the EMI of the power supply, the device provides a selectable Dual Random Spread Spectrum, which reduces the EMI over a wide frequency range.

The device features an accurate peak current limit over the input voltage, which avoids overdesigning power inductor. Low operating current and pulse-skipping operation improve efficiency at light loads.

The device has built-in protection features such as overvoltage protection, line UVLO, thermal shutdown, and selectable Hiccup mode overload protection. Additional features include low shutdown I Q, programmable soft start, precision reference, a power-good indicator, and external clock synchronization.

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Technical documentation

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Top documentation	Type	Title	Format options	Date
*	Data sheet	LM5157 2.2-MHz Wide VIN 50-V Boost/SEPIC/Flyback Converter with Dual Random Spread Spectrum datasheet (Rev. A)	PDF \| HTML	May 3, 2023
	Application brief	Avoiding Pulse Skip Operation at Light Load Conditions for Asynchronous Boost Converter Designs	PDF \| HTML	Sep 16, 2025
	Application note	How to Implement the Soft Start in a Flyback	PDF \| HTML	Jul 10, 2023
	Application note	How to Design an Isolated Flyback Converter Using LM5157x/LM5158x (Rev. A)	PDF \| HTML	Mar 16, 2023
	Application note	Basic Calculation of a Coupled Inductor SEPIC Power Stage	PDF \| HTML	Mar 13, 2023
	Certificate	LM5157EVM-SEPIC EU RoHS Declaration of Conformity (DoC)		Dec 23, 2021
	Application note	How to Design a Boost Converter Using LM5157x, LM5158x	PDF \| HTML	Nov 11, 2021
	Technical article	Lowering audible noise in automotive applications with TI’s DRSS technology	PDF \| HTML	Mar 18, 2021

Design & development

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

Evaluation board

LM5157EVM-BST — LM5157 boost converter evaluation module

The LM5157EVM-BST evaluation module showcases the features and performance of the LM5157 device as a wide input voltage boost converter with dual random spread spectrum. The standard configuration is designed to provide a regulated output of 12 V at 1.6 A from an input of 3 V to (...)

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Evaluation board

LM5157EVM-FLY — LM5157 flyback boost converter evaluation module

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 (...)

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Evaluation board

LM5157EVM-SEPIC — LM5157 evaluation module for SEPIC

The LM5157EVM-SEPIC evaluation module showcases the features and performance of the LM5157 as wide input non-synchronous SEPIC converter. The standard configuration is designed to provide a regulated output of 12 V at up to 1 A from an input of 4 V to 32 V, switching at 2.1 MHz.

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Simulation model