LM5145

ACTIVE

75V Synchronous Buck Controller With Wide Input Voltage and Duty Cycle Ranges

Product details

Vin (min) (V) 6 Vin (max) (V) 75 Iout (max) (A) 30 Operating temperature range (°C) -40 to 125 Control mode Voltage mode Topology Buck Rating Catalog Vout (min) (V) 0.8 Vout (max) (V) 60 Features Adjustable current limit, Enable, Frequency synchronization, Light Load Efficiency, Power good, Pre-Bias Start-Up, Synchronous Rectification, Tracking, UVLO adjustable Iq (typ) (µA) 1500 Duty cycle (max) (%) 99 Number of phases 1
Vin (min) (V) 6 Vin (max) (V) 75 Iout (max) (A) 30 Operating temperature range (°C) -40 to 125 Control mode Voltage mode Topology Buck Rating Catalog Vout (min) (V) 0.8 Vout (max) (V) 60 Features Adjustable current limit, Enable, Frequency synchronization, Light Load Efficiency, Power good, Pre-Bias Start-Up, Synchronous Rectification, Tracking, UVLO adjustable Iq (typ) (µA) 1500 Duty cycle (max) (%) 99 Number of phases 1
VQFN (RGY) 20 15.75 mm² 4.5 x 3.5
  • Versatile synchronous buck DC/DC controller
    • Wide input voltage range of 6 V to 75 V
    • 0.8-V reference with ±1% feedback accuracy
    • Adjustable output voltage from 0.8 V to 60 V
    • 40-ns tON(min) for high VIN / VOUT ratio
    • 140-ns tOFF(min) for low dropout
    • Optimized for CISPR 32 requirements
  • Switching frequency from 100 kHz to 1 MHz
    • SYNC In and SYNC Out capability
    • Selectable diode emulation or FPWM
  • 7.5-V gate drivers for standard VTH MOSFETs
    • 14-ns adaptive dead-time control
    • 2.3-A source and 3.5-A sink capability
    • Low-side soft start for prebiased start-up
  • Fast line and load transient response
    • Voltage-mode control with line feedforward
    • High gain-bandwidth error amplifier
  • Inherent protection features for robust design
    • Adjustable output voltage soft start
    • Hiccup-mode overcurrent protection
    • Input UVLO with hysteresis
    • VCC and gate-drive UVLO protection
    • Precision enable input and open-drain PGOOD indicator for sequencing and control
    • Thermal shutdown protection with hysteresis
  • 20-pin VQFN package with wettable flanks
  • Create a custom design using the LM5145 with WEBENCH Power Designer
  • Versatile synchronous buck DC/DC controller
    • Wide input voltage range of 6 V to 75 V
    • 0.8-V reference with ±1% feedback accuracy
    • Adjustable output voltage from 0.8 V to 60 V
    • 40-ns tON(min) for high VIN / VOUT ratio
    • 140-ns tOFF(min) for low dropout
    • Optimized for CISPR 32 requirements
  • Switching frequency from 100 kHz to 1 MHz
    • SYNC In and SYNC Out capability
    • Selectable diode emulation or FPWM
  • 7.5-V gate drivers for standard VTH MOSFETs
    • 14-ns adaptive dead-time control
    • 2.3-A source and 3.5-A sink capability
    • Low-side soft start for prebiased start-up
  • Fast line and load transient response
    • Voltage-mode control with line feedforward
    • High gain-bandwidth error amplifier
  • Inherent protection features for robust design
    • Adjustable output voltage soft start
    • Hiccup-mode overcurrent protection
    • Input UVLO with hysteresis
    • VCC and gate-drive UVLO protection
    • Precision enable input and open-drain PGOOD indicator for sequencing and control
    • Thermal shutdown protection with hysteresis
  • 20-pin VQFN package with wettable flanks
  • Create a custom design using the LM5145 with WEBENCH Power Designer

The LM5145 75-V synchronous buck controller regulates from a high input voltage source or from an input rail subject to high voltage transients, minimizing the need for external surge suppression components. A high-side switch minimum on-time of 40 ns gives large step-down ratios, enabling the direct step-down conversion from a 48-V nominal input to low-voltage rails for reduced system complexity and solution cost. The LM5145 continues to operate during input voltage dips as low as 6 V, at nearly 100% duty cycle if needed, making it an excellent choice for high-performance industrial control, robotic, datacom, and RF power applications.

Forced-PWM (FPWM) operation eliminates switching frequency variation to minimize EMI, while user-selectable diode emulation lowers current consumption at light-load conditions. The adjustable switching frequency as high as 1 MHz can be synchronized to an external clock source to eliminate beat frequencies in noise-sensitive applications.

The LM5145 75-V synchronous buck controller regulates from a high input voltage source or from an input rail subject to high voltage transients, minimizing the need for external surge suppression components. A high-side switch minimum on-time of 40 ns gives large step-down ratios, enabling the direct step-down conversion from a 48-V nominal input to low-voltage rails for reduced system complexity and solution cost. The LM5145 continues to operate during input voltage dips as low as 6 V, at nearly 100% duty cycle if needed, making it an excellent choice for high-performance industrial control, robotic, datacom, and RF power applications.

Forced-PWM (FPWM) operation eliminates switching frequency variation to minimize EMI, while user-selectable diode emulation lowers current consumption at light-load conditions. The adjustable switching frequency as high as 1 MHz can be synchronized to an external clock source to eliminate beat frequencies in noise-sensitive applications.

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Technical documentation

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Type Title Date
* Data sheet LM5145 75-V Synchronous Buck DC/DC Controller With Wide Duty Cycle Range datasheet (Rev. B) PDF | HTML 19 Nov 2020
Application note Controller to Converter – Design Considerations for 24V and 48V Systems PDF | HTML 02 Oct 2024
Analog Design Journal Control-Mode Quick Reference Guide (Rev. B) PDF | HTML 29 Aug 2023
E-book An Engineer’s Guide to Low EMI in DC/DC Regulators 21 Apr 2021
Application note An Accurate Approach for Calculating the Efficiency of a Synchronous Buck Conver 02 Jul 2020
Application note Wide-Vin Battery-Charger Using SMBus MSP430 MCUs and bq Fuel Gauges (Rev. B) PDF | HTML 12 Jul 2019
White paper Valuing wide VIN, low EMI synchronous buck circuits for cost-driven, demanding a (Rev. A) 10 Apr 2019
Application brief IC Package Features Lead to Higher Reliability in Automotive Systems 20 Feb 2019
Application brief Improving RF Power Amplifier Efficiency in 5G Radio Systems 05 Sep 2018
EVM User's guide LM5146-Q1EVM User's Guide 10 Aug 2018
Technical article A review of EMI standards, part 2 – radiated emissions PDF | HTML 05 Jul 2018
Technical article A review of EMI standards, part 1 – conducted emissions PDF | HTML 28 Jun 2018
White paper An overview of radiated EMI specifications for power supplies 05 Jun 2018
Selection guide DC/DC Buck Controller Solutions Selection Guide 06 Feb 2018
White paper An overview of conducted EMI specifications for power supplies 01 Feb 2018
Application brief Improve DC/DC Regulator EMI for Free with Optimized Power Stage Layout 13 Nov 2017
Technical article How to design a simple two-phase current-sharing synchronous buck regulator using PDF | HTML 03 Nov 2017
Technical article Synchronous buck controller solutions support wide VIN performance and flexibility PDF | HTML 29 Jun 2017
EVM User's guide LM5145EVM-HD-20A High Density Evaluation Module (Rev. A) 07 Jun 2017
Analog Design Journal Reduce buck-converter EMI and voltage stress by minimizing inductive parasitics 21 Jul 2016
Technical article High Density PCB Layout of DC/DC Converters, Part 2 PDF | HTML 16 Sep 2015
Technical article High Density PCB Layout of DC/DC Converters, Part 1 PDF | HTML 12 Sep 2015
Application note Power Topology - Buck Converter 16 Aug 2010
Application note Load-Sharing TPS40050 Modules Using the UCC39002 Load-Share Controller 13 Apr 2004
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

LM5145EVM-HD-20A — LM5145 Wide VIN Synchronous Buck Controller High Density Evaluation Module

The LM5145EVM-HD-20A high density evaluation module (EVM) is designed to showcase the performance of the LM5145 high performance, synchronous buck DC-DC buck controller with wide input voltage range. The design is packaged in a miniature footprint with low component count. It operates over a wide (...)
User guide: PDF
Not available on TI.com
Simulation model

LM5145 PSpice Unencrypted Transient Model (Rev. C)

SNVMB65C.ZIP (150 KB) - PSpice Model
Calculation tool

LM5145DESIGN-CALC LM5145 Quickstart Design Tool

Welcome to the LM5145 Quickstart Design Tool. This standalone tool facilitates and assists the power supply engineer with the design of a DC/DC buck regulator based on the LM5145 75V synchronous buck controller. As such, the user can expeditiously arrive at an optimized design to meet the (...)

Supported products & hardware

Supported products & hardware

Products
AC/DC & DC/DC controllers (external FET)
LM5145 75V Synchronous Buck Controller With Wide Input Voltage and Duty Cycle Ranges LM5145-Q1 Automotive 75-V synchronous buck DC/DC controller with wide duty-cycle range
Hardware development
Evaluation board
LM5145EVM-HD-20A LM5145 Wide VIN Synchronous Buck Controller High Density Evaluation Module
Software
Calculation tool
LM5145DESIGN-CALC LM5145 Synchronous Buck Controller Design Tool
Calculation tool

SNVR510 LM5145 Inverting Buck-Boost Quickstart Calculator

Supported products & hardware

Supported products & hardware

Products
AC/DC & DC/DC controllers (external FET)
LM5145 75V Synchronous Buck Controller With Wide Input Voltage and Duty Cycle Ranges
PCB layout

LM5146-Q1-EVM12V PCB Layout Files

SNVR473.ZIP (7838 KB)
PCB layout

LM5145EVM-HD-20A PCB Layout Files

SNVR500.ZIP (1493 KB)
Reference designs

PMP20178 — 57W Output Synchronous Buck Converter for Telecom Reference Design

PMP20178 is a voltage-mode synchronous buck converter reference design rated for 5.2V output at 11A from an input voltage of 15V to 60V. This design uses the LM5145 synchronous buck controller at a switching frequency of 200 kHz. Features include power good, synchronization and trim functions.
Test report: PDF
Schematic: PDF
Package Pins CAD symbols, footprints & 3D models
VQFN (RGY) 20 Ultra Librarian

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