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LM25145

ACTIVE

6V to 42V Synchronous Buck DC-DC Controller With Wide Duty Cycle Range

Product details

Vin (min) (V) 6 Vin (max) (V) 42 Vout (min) (V) 0.8 Vout (max) (V) 40 Iout (max) (A) 30 Iq (typ) (mA) 1.8 Switching frequency (min) (kHz) 100 Switching frequency (max) (kHz) 1000 Features Adjustable current limit, Enable, Frequency synchronization, Light Load Efficiency, Power good, Pre-Bias Start-Up, Synchronous Rectification, Tracking, UVLO adjustable Operating temperature range (°C) -40 to 125 Regulated outputs (#) 1 Number of phases 1 Rating Catalog Control mode Voltage mode Type Controller
Vin (min) (V) 6 Vin (max) (V) 42 Vout (min) (V) 0.8 Vout (max) (V) 40 Iout (max) (A) 30 Iq (typ) (mA) 1.8 Switching frequency (min) (kHz) 100 Switching frequency (max) (kHz) 1000 Features Adjustable current limit, Enable, Frequency synchronization, Light Load Efficiency, Power good, Pre-Bias Start-Up, Synchronous Rectification, Tracking, UVLO adjustable Operating temperature range (°C) -40 to 125 Regulated outputs (#) 1 Number of phases 1 Rating Catalog Control mode Voltage mode Type Controller
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 42 V
    • Adjustable Output Voltage From 0.8 V to 40 V
  • Meets EN55022 / CISPR 22 EMI Standards
  • Lossless RDS(on) or Shunt Current Sensing
  • Switching Frequency From 100 kHz to 1 MHz
    • SYNC In and SYNC Out Capability
  • 40-ns Minimum On-Time for High VIN / VOUT Ratio
  • 140-ns Minimum Off-Time for Low Dropout
  • 0.8-V Reference With ±1% Feedback Accuracy
  • 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
  • Adjustable Soft-Start or Optional Voltage Tracking
  • Fast Line and Load Transient Response
    • Voltage-Mode Control With Line Feedforward
    • High Gain-Bandwidth Error Amplifier
  • Precision Enable Input and Open-Drain Power Good Indicator for Sequencing and Control
  • Inherent Protection Features for Robust Design
    • Hiccup Mode Overcurrent Protection
    • Input UVLO With Hysteresis
    • VCC and Gate Drive UVLO Protection
    • Thermal Shutdown Protection With Hysteresis
  • VQFN-20 Package With Wettable Flanks
  • Create a Custom Design Using the LM25145 With WEBENCH® Power Designer
  • Versatile Synchronous Buck DC-DC Controller
    • Wide Input Voltage Range of 6 V to 42 V
    • Adjustable Output Voltage From 0.8 V to 40 V
  • Meets EN55022 / CISPR 22 EMI Standards
  • Lossless RDS(on) or Shunt Current Sensing
  • Switching Frequency From 100 kHz to 1 MHz
    • SYNC In and SYNC Out Capability
  • 40-ns Minimum On-Time for High VIN / VOUT Ratio
  • 140-ns Minimum Off-Time for Low Dropout
  • 0.8-V Reference With ±1% Feedback Accuracy
  • 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
  • Adjustable Soft-Start or Optional Voltage Tracking
  • Fast Line and Load Transient Response
    • Voltage-Mode Control With Line Feedforward
    • High Gain-Bandwidth Error Amplifier
  • Precision Enable Input and Open-Drain Power Good Indicator for Sequencing and Control
  • Inherent Protection Features for Robust Design
    • Hiccup Mode Overcurrent Protection
    • Input UVLO With Hysteresis
    • VCC and Gate Drive UVLO Protection
    • Thermal Shutdown Protection With Hysteresis
  • VQFN-20 Package With Wettable Flanks
  • Create a Custom Design Using the LM25145 With WEBENCH® Power Designer

The LM25145 42-V synchronous buck controller is designed to regulate 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 facilitates large step-down ratios, enabling the direct step-down conversion from a 24 V nominal input to low-voltage rails for reduced system complexity and solution cost. The LM25145 continues to operate during input voltage dips as low as 6 V, at nearly 100% duty cycle if needed, making it well suited for high-performance industrial control, robotic, datacom, and RF power amplifier applications.

Forced-PWM (FPWM) operation eliminates frequency variation to minimize EMI, while a user-selectable diode emulation feature lowers current consumption at light-load conditions. Cycle-by-cycle overcurrent protection is accomplished by measuring the voltage drop across the low-side MOSFET or by using an optional current sense resistor. 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 LM25145 voltage-mode controller drives external high-side and low-side N-channel power switches with robust 7.5-V gate drivers suitable for standard-threshold MOSFETs. Adaptively-timed gate drivers with 2.3-A source and 3.5-A sink capability minimize body diode conduction during switching transitions, reducing switching losses and improving thermal performance when driving MOSFETs at high input voltage and high frequency. The LM25145 can be powered from the output of the switching regulator or another available source, further improving efficiency.

A 180° out-of-phase clock output relative to the internal oscillator at SYNCOUT is ideal for cascaded or multi-channel power supplies to reduce input capacitor ripple current and EMI filter size. Additional features of the LM25145 include a configurable soft-start, an open-drain Power Good monitor for fault reporting and output monitoring, monotonic start-up into prebiased loads, integrated VCC bias supply regulator and bootstrap diode, external power supply tracking, precision enable input with hysteresis for adjustable line undervoltage lockout (UVLO), hiccup-mode overload protection, and thermal shutdown protection with automatic recovery.

The LM25145 controller is offered in a 3.5-mm × 4.5-mm thermally-enhanced, 20-pin VQFN package with additional spacing for high-voltage pins and wettable flanks for optical inspection of solder joint fillets.

The LM25145 42-V synchronous buck controller is designed to regulate 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 facilitates large step-down ratios, enabling the direct step-down conversion from a 24 V nominal input to low-voltage rails for reduced system complexity and solution cost. The LM25145 continues to operate during input voltage dips as low as 6 V, at nearly 100% duty cycle if needed, making it well suited for high-performance industrial control, robotic, datacom, and RF power amplifier applications.

Forced-PWM (FPWM) operation eliminates frequency variation to minimize EMI, while a user-selectable diode emulation feature lowers current consumption at light-load conditions. Cycle-by-cycle overcurrent protection is accomplished by measuring the voltage drop across the low-side MOSFET or by using an optional current sense resistor. 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 LM25145 voltage-mode controller drives external high-side and low-side N-channel power switches with robust 7.5-V gate drivers suitable for standard-threshold MOSFETs. Adaptively-timed gate drivers with 2.3-A source and 3.5-A sink capability minimize body diode conduction during switching transitions, reducing switching losses and improving thermal performance when driving MOSFETs at high input voltage and high frequency. The LM25145 can be powered from the output of the switching regulator or another available source, further improving efficiency.

A 180° out-of-phase clock output relative to the internal oscillator at SYNCOUT is ideal for cascaded or multi-channel power supplies to reduce input capacitor ripple current and EMI filter size. Additional features of the LM25145 include a configurable soft-start, an open-drain Power Good monitor for fault reporting and output monitoring, monotonic start-up into prebiased loads, integrated VCC bias supply regulator and bootstrap diode, external power supply tracking, precision enable input with hysteresis for adjustable line undervoltage lockout (UVLO), hiccup-mode overload protection, and thermal shutdown protection with automatic recovery.

The LM25145 controller is offered in a 3.5-mm × 4.5-mm thermally-enhanced, 20-pin VQFN package with additional spacing for high-voltage pins and wettable flanks for optical inspection of solder joint fillets.

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Technical documentation

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Type Title Date
* Data sheet LM25145 6-V to 42-V Synchronous Buck DC-DC Controller With Wide Duty Cycle Range datasheet PDF | HTML 22 Jun 2017
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
Selection guide Buck Converter Quick Reference Guide (Rev. B) 08 Apr 2021
White paper Valuing wide VIN, low EMI synchronous buck circuits for cost-driven, demanding a (Rev. A) 10 Apr 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 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

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

LM25145 PSpice Transient Model (Rev. A)

SNVMBB9A.ZIP (125 KB) - PSpice Model
Calculation tool

LM25145DESIGN-CALC — LM25145 Synchronous Buck Controller Design Tool

Welcome to the LM25145 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 LM25145 42V synchronous buck controller. As such, the user can expeditiously arrive at an optimized design to meet the (...)
PCB layout

LM5146-Q1-EVM12V PCB Layout Files

SNVR473.ZIP (7838 KB)
PCB layout

LM5145EVM-HD-20A PCB Layout Files

SNVR500.ZIP (1493 KB)
Simulation tool

PSPICE-FOR-TI — PSpice® for TI design and simulation tool

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 (...)
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VQFN (RGY) 20 View options

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