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LM5181

ACTIVE

65-VIN no-opto flyback converter with 100-V, 0.75-A integrated MOSFET

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Data sheet

LM5181

ACTIVE
Data sheet Order now

Product details

Iout (max) (A) 0.75 Vin (min) (V) 4.5 Vin (max) (V) 65 Topology PSR flyback Switching frequency (min) (kHz) 12 Switching frequency (max) (kHz) 350 Features Enable, Integrated Switch, Light load efficiency, Pre-bias soft start, UVLO adjustable Control mode Peak current mode Rating Catalog Operating temperature range (°C) -40 to 150
Iout (max) (A) 0.75 Vin (min) (V) 4.5 Vin (max) (V) 65 Topology PSR flyback Switching frequency (min) (kHz) 12 Switching frequency (max) (kHz) 350 Features Enable, Integrated Switch, Light load efficiency, Pre-bias soft start, UVLO adjustable Control mode Peak current mode Rating Catalog Operating temperature range (°C) -40 to 150
WSON (NGU) 8 16 mm² 4 x 4
  • Functional Safety-Capable
  • Designed for reliable and rugged applications
    • Wide input voltage range of 4.5 V to 65 V with operation down to 3.5 V after start-up
    • Robust solution with only one component crossing the isolation barrier
    • ±1.5% total output regulation accuracy
    • Optional VOUT temperature compensation
    • 6-ms internal or programmable soft start
    • Input UVLO and thermal shutdown protection
    • Hiccup-mode overcurrent fault protection
    • –40°C to +150°C junction temperature range
  • Integration reduces solution size and cost
    • Integrated 100-V, 0.4-Ω power MOSFET
    • No opto-coupler or transformer auxiliary winding required for VOUT regulation
    • Internal loop compensation
  • High-efficiency PSR flyback operation
    • Quasi-resonant MOSFET turn-off in BCM
    • Low input quiescent current
    • External bias option for improved efficiency
    • Single- and multi-output implementations
  • Ultra-low conducted and radiated EMI signatures
    • Soft switching avoids diode reverse recovery
    • Optimized for CISPR 32 EMI requirements
  • Create a custom regulator design using WEBENCH Power Designer
  • Functional Safety-Capable
  • Designed for reliable and rugged applications
    • Wide input voltage range of 4.5 V to 65 V with operation down to 3.5 V after start-up
    • Robust solution with only one component crossing the isolation barrier
    • ±1.5% total output regulation accuracy
    • Optional VOUT temperature compensation
    • 6-ms internal or programmable soft start
    • Input UVLO and thermal shutdown protection
    • Hiccup-mode overcurrent fault protection
    • –40°C to +150°C junction temperature range
  • Integration reduces solution size and cost
    • Integrated 100-V, 0.4-Ω power MOSFET
    • No opto-coupler or transformer auxiliary winding required for VOUT regulation
    • Internal loop compensation
  • High-efficiency PSR flyback operation
    • Quasi-resonant MOSFET turn-off in BCM
    • Low input quiescent current
    • External bias option for improved efficiency
    • Single- and multi-output implementations
  • Ultra-low conducted and radiated EMI signatures
    • Soft switching avoids diode reverse recovery
    • Optimized for CISPR 32 EMI requirements
  • Create a custom regulator design using WEBENCH Power Designer

The LM5181 is a primary-side regulated (PSR) flyback converter with high efficiency over a wide input voltage range of 4.5 V to 65 V. The isolated output voltage is sampled from the primary-side flyback voltage, eliminating the need for an optocoupler, voltage reference, or third winding from the transformer for output voltage regulation.

The high level of integration results in a simple, reliable and high-density design with only one component crossing the isolation barrier. Boundary conduction mode (BCM) switching enables a compact magnetic solution and better than ±1.5% load and line regulation performance. An integrated 100-V power MOSFET provides output power up to 4 W with enhanced headroom for line transients.

The LM5181 flyback converter is available in a 8-pin, 4-mm × 4-mm, thermally-enhanced WSON package with 0.8-mm pin pitch.

The LM5181 is a primary-side regulated (PSR) flyback converter with high efficiency over a wide input voltage range of 4.5 V to 65 V. The isolated output voltage is sampled from the primary-side flyback voltage, eliminating the need for an optocoupler, voltage reference, or third winding from the transformer for output voltage regulation.

The high level of integration results in a simple, reliable and high-density design with only one component crossing the isolation barrier. Boundary conduction mode (BCM) switching enables a compact magnetic solution and better than ±1.5% load and line regulation performance. An integrated 100-V power MOSFET provides output power up to 4 W with enhanced headroom for line transients.

The LM5181 flyback converter is available in a 8-pin, 4-mm × 4-mm, thermally-enhanced WSON package with 0.8-mm pin pitch.
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Technical documentation

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Type Title Date
* Data sheet LM5181 65-VIN PSR Flyback DC/DC Converter with 100-V, 0.75-A Integrated MOSFET datasheet (Rev. A) PDF | HTML 25 Jan 2021
Technical article Mitigating CMTI on a PSR flyback for SiC-based traction inverter designs PDF | HTML 05 Jan 2024
Analog Design Journal Why use PSR‐flyback isolated converters in dual‐battery mHEV systems (Rev. A) PDF | HTML 25 May 2023
Application note Designing High Voltage Power Supply for Ultrasound Smart Probes (Rev. A) PDF | HTML 16 May 2023
Analog Design Journal Selecting output caps to optimize ripple and stability in PSR flyback converters (Rev. B) PDF | HTML 04 May 2023
Product overview Isolated Power Topologies for PLC I/O Modules and Other Low-Power Applications PDF | HTML 09 Nov 2022
Application note LM5181 Bipolar + and - 18 V Output Design for Signal Chains in PLC Applications PDF | HTML 29 Oct 2021
Application note Topology Selection for Isolated Power Supplies in Patient Monitor (Rev. A) PDF | HTML 02 Sep 2020
Functional safety information LMx518x-Q1 Functional Safety FIT Rate and Failure Mode Distribution (Rev. A) PDF | HTML 26 Jun 2020
Technical article How to raise regulation performance with a stacked-output PSR flyback DC/DC conver PDF | HTML 02 Jun 2020
Analog Design Journal How an auxless PSR-flyback converter can increase PLC reliability and density 30 Sep 2019
White paper An overview of radiated EMI specifications for power supplies 05 Jun 2018
White paper An overview of conducted EMI specifications for power supplies 01 Feb 2018
Application brief PSR Flyback DC/DC Converter Transformer Design for mHEV Applications 13 Nov 2017
Application note Seminar 900 Topic 2 - Snubber Circuits: Theory, Design and Application 15 Feb 2001

Design & development

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

Evaluation board

LM5180EVM-DUAL — Wide VIN PSR flyback converter dual-output evaluation module

The LM5180EVM-DUAL evaluation module (EVM) is designed to showcase the performance of the LM5180 PSR flyback converter with wide input voltage range. The design is packaged in a miniature footprint with low component count. It operates over a wide input voltage range of 10 V to 65 V to deliver a (...)
User guide: PDF
Not available on TI.com
Evaluation board

LM5180EVM-S05 — Wide VIN PSR flyback converter single-output evaluation module

The LM5180EVM-S05 evaluation module (EVM) is designed to showcase the performance of the LM5180 PSR flyback converter with wide input voltage range. The design is packaged in a miniature footprint with low component count. It operates over a wide input voltage range of 10 V to 65 V to deliver a (...)
User guide: PDF
Not available on TI.com
Simulation model

LM5181-Q1 PSpice Transient Model (Rev. A)

SNVMBZ9A.ZIP (130 KB) - PSpice Model
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Calculation tool

LM5181DESIGN-CALC — LM5181 PSR Flyback Converter Quickstart Design Tool

Welcome to the LM5181 quickstart design tool. This standalone tool facilitates and assists the power supply engineer with the design of a DC/DC flyback regulator based on the LM5181 PSR flyback converter. As such, the user can expeditiously arrive at an optimized design to meet the application (...)
Supported products & hardware

Supported products & hardware

Products
AC/DC & DC/DC converters (integrated FET)
LM5181 — 65-VIN no-opto flyback converter with 100-V, 0.75-A integrated MOSFET LM5181-Q1 — Automotive 65-VIN no-opto flyback DC/DC converter with 100-V, 0.75-A integrated MOSFET
Software
Calculation tool
LM5181DESIGN-CALC — LM5181 PSR flyback converter design tool
Download
Reference designs

PMP31177 — 1-W primary-side regulated flyback reference design

This 26.54 mm × 11.68 mm × 5.6-mm height board is optimized to leverage the performance of the LM5181 PSR Flyback converter. The board operates over an input voltage range of 18 V to 32 V to deliver 24-V and 3.3‑V outputs at currents of up to 40 mA and 15 mA respectively. Operating (...)
Test report: PDF
Package Pins Download
WSON (NGU) 8 View options
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