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LM5161-Q1

ACTIVE

Wide Input 4.5-V to 100-V, 1-A Synchronous Buck / Fly-Buck Converter

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Data sheet

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LM5164-Q1 ACTIVE 6-V to 100-V input, 1-A synchronous DC-DC buck converter with ultra-low IQ Ultra-low EMI emission.

LM5161-Q1

ACTIVE
Data sheet Order now

Product details

Rating Automotive Operating temperature range (°C) -40 to 125 Topology Buck, Flybuck Type Converter Iout (max) (A) 1 Vin (min) (V) 4.5 Vin (max) (V) 100 Switching frequency (min) (kHz) 50 Switching frequency (max) (kHz) 1000 Features Enable, Light load efficiency, Pre-bias soft start, Synchronous rectification Control mode COT with emulated ripple, Constant on-time (COT) Vout (min) (V) 2 Vout (max) (V) 92 Duty cycle (max) (%) 92 Switch current limit (typ) (A) 1.6
Rating Automotive Operating temperature range (°C) -40 to 125 Topology Buck, Flybuck Type Converter Iout (max) (A) 1 Vin (min) (V) 4.5 Vin (max) (V) 100 Switching frequency (min) (kHz) 50 Switching frequency (max) (kHz) 1000 Features Enable, Light load efficiency, Pre-bias soft start, Synchronous rectification Control mode COT with emulated ripple, Constant on-time (COT) Vout (min) (V) 2 Vout (max) (V) 92 Duty cycle (max) (%) 92 Switch current limit (typ) (A) 1.6
HTSSOP (PWP) 14 32 mm² 5 x 6.4
  • Qualified for Automotive Applications
  • AEC-Q100 Qualified With the Following Results:
    • Device Temperature Grade 1: –40°C to 125°C Ambient Operating Temperature Range
    • Device HBM ESD Classification Level 2
    • Device CDM ESD Classification Level C5
  • Wide 4.5-V to 100-V Input Voltage Range
  • Integrated High-Side and Low-Side Switches
    • No Schottky Diode Required
  • 1-A Maximum Load Current
  • Constant ON-Time Control
    • No External Loop Compensation
    • Fast Transient Response
  • Selectable DCM Buck Operation at Light Load
  • CCM Option Supports Multi-Output Fly-Buck™
  • No External Ripple circuit needed (at FPWM = 0)
  • Nearly Constant Switching Frequency
  • Frequency Adjustable Up to 1 MHz
  • Programmable Soft-Start Time
  • Prebias Start-Up
  • Peak Current Limiting Protection
  • Adjustable Input UVLO and Hysteresis
  • ±1% Feedback Voltage Reference
  • Thermal Shutdown Protection
  • Create a Custom Design Using the LM5161-Q1 With the WEBENCH® Power Designer
  • Qualified for Automotive Applications
  • AEC-Q100 Qualified With the Following Results:
    • Device Temperature Grade 1: –40°C to 125°C Ambient Operating Temperature Range
    • Device HBM ESD Classification Level 2
    • Device CDM ESD Classification Level C5
  • Wide 4.5-V to 100-V Input Voltage Range
  • Integrated High-Side and Low-Side Switches
    • No Schottky Diode Required
  • 1-A Maximum Load Current
  • Constant ON-Time Control
    • No External Loop Compensation
    • Fast Transient Response
  • Selectable DCM Buck Operation at Light Load
  • CCM Option Supports Multi-Output Fly-Buck™
  • No External Ripple circuit needed (at FPWM = 0)
  • Nearly Constant Switching Frequency
  • Frequency Adjustable Up to 1 MHz
  • Programmable Soft-Start Time
  • Prebias Start-Up
  • Peak Current Limiting Protection
  • Adjustable Input UVLO and Hysteresis
  • ±1% Feedback Voltage Reference
  • Thermal Shutdown Protection
  • Create a Custom Design Using the LM5161-Q1 With the WEBENCH® Power Designer

The LM5161-Q1 is a 100-V, 1-A synchronous step-down converter with integrated high-side and low-side MOSFETs. The constant-ON-time control scheme requires no loop compensation and supports high step-down ratios with fast transient response. An internal feedback amplifier maintains ±1% output voltage regulation over the entire operating temperature range. The ON-time varies inversely with input voltage resulting in nearly constant switching frequency. Peak and valley current limit circuits protect against overload conditions. The under-voltage lockout (EN/UVLO) circuit provides independently adjustable input undervoltage threshold and hysteresis. The FPWM input pin in LM5161-Q1 selects either the forced continuous conduction mode (CCM) under all load levels or the discontinuous conduction mode (DCM) under light or no load conditions. When operating in forced CCM, the LM5161-Q1 supports the multiple output and isolated Fly-Buck applications. When programmed for the DCM operation, the LM5161-Q1 provides a tightly regulated buck output without any additional external feedback ripple injection circuit.

The LM5161-Q1 is a 100-V, 1-A synchronous step-down converter with integrated high-side and low-side MOSFETs. The constant-ON-time control scheme requires no loop compensation and supports high step-down ratios with fast transient response. An internal feedback amplifier maintains ±1% output voltage regulation over the entire operating temperature range. The ON-time varies inversely with input voltage resulting in nearly constant switching frequency. Peak and valley current limit circuits protect against overload conditions. The under-voltage lockout (EN/UVLO) circuit provides independently adjustable input undervoltage threshold and hysteresis. The FPWM input pin in LM5161-Q1 selects either the forced continuous conduction mode (CCM) under all load levels or the discontinuous conduction mode (DCM) under light or no load conditions. When operating in forced CCM, the LM5161-Q1 supports the multiple output and isolated Fly-Buck applications. When programmed for the DCM operation, the LM5161-Q1 provides a tightly regulated buck output without any additional external feedback ripple injection circuit.
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Technical documentation

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Type Title Date
* Data sheet LM5161-Q1 Wide Input 100-V, 1-A Synchronous Buck/Fly-Buck™ Converter datasheet (Rev. A) PDF | HTML 30 Nov 2017
White paper Valuing wide VIN, low EMI synchronous buck circuits for cost-driven, demanding a (Rev. A) 10 Apr 2019
Application note Stability Analysis and Design of COT Type-3 Ripple Circuit 20 Mar 2019
Application brief Powering Drones With a Wide VIN DC-DC Converter (Rev. A) 05 Feb 2019
Application note EMI and Thermal Design Tips and Tricks for 48-V IGBT/SiC/GaN Automotive Supply 27 Jul 2018
Technical article Why a wide VIN DC/DC converter is a good fit for high-cell-count battery-powered d PDF | HTML 21 Nov 2017
Technical article Simplifying 100V wide VIN power conversion PDF | HTML 11 Nov 2016
EVM User's guide LM5161 Fly-Buck (Isolated Buck) EVM User’s Guide (Rev. A) 19 Aug 2016
EVM User's guide LM5161PWPBKEVM Buck Evaluation Module User's Guide (Rev. A) 19 Aug 2016
Technical article Create a Fly-Buck™ converter in WEBENCH® Power Designer PDF | HTML 09 Oct 2015
White paper Designing isolated rails on the fly with Fly-Buck™ converters 29 Sep 2015
Technical article How to design for EMC and isolation with Fly-Buck™ converters PDF | HTML 28 Jul 2015
Application note Is Your IGBT Gate-Driver Power Supply Optimized 12 Mar 2015
Analog Design Journal Fly-Buck(TM) converter provides EMC and isolation in PLC applications 29 Jan 2015
Application note AN-2292 Designing an Isolated Buck (Fly-Buck) Converter (Rev. C) 17 Dec 2014
White paper Wide VIN power management ICs simplify white paper (Rev. A) 19 Sep 2013

Design & development

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

Evaluation board

LM5161PWPBKEVM — LM5161 Wide VIN Synchronous Buck Converter Constant On-Time Evaluation Module

The LM5161PWPBKEVM evaluation board provides a fully functional buck regulator, employing the constant on-time (COT) operating principle. This evaluation board provides a 12-V output over an input range of 15V to 80 V. The circuit delivers load currents to 1.0 A. The application schematic is setup (...)
User guide: PDF
Not available on TI.com
Evaluation board

LM5161PWPFBKEVM — LM5161 Wide VIN Fly-Buck Evaluation Module

The LM5161PWPFBKEVM evaluation board provides a fully functional Fly-buck regulator, employing the constant on-time (COT) operating principle. This evaluation board provides a 12-V secondary isolated output voltage over an input range of 36V to 72 V. The circuit delivers secondary output load (...)
User guide: PDF
Not available on TI.com
Simulation model

LM5161 PSpice Buck and Fly-Buck Transient Model

SNVMAV3.ZIP (499 KB) - PSpice Model
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Simulation model

LM5161 Unencrypted PSpice Buck and Fly-Buck Transient Model

SNVMAV4.ZIP (3 KB) - PSpice Model
Download
Reference designs

PMP30603 — -60 V inverting buck-boost reference design

This tiny reference design delivers -60-V output voltage from an input voltage around 5 V typically generated by an automotive pre regulator. The controller in that circuit is LM5161-Q1 providing two internal MOSFETs. Overall, this converter is used as auxiliary supply for LIDAR applications. 
Test report: PDF
Schematic: PDF
Reference designs

PMP15007 — Dual-Output LM5161-Q1 Fly-Buck™ Reference Design With an Ultra-Small Coupled Inductor

PMP15007 uses the LM5161-Q1 in a Fly-Buck topology with the primary and secondary output both set to 5V nominal. The circuit accommodates a voltage input range from 36V to 72V, ideal for the 48V nominal input rail. While the primary side is set at 5.32V nominally, the secondary isolated side sees (...)
Test report: PDF
Schematic: PDF
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HTSSOP (PWP) 14 Ultra Librarian
TI's Standard Terms and Conditions for Evaluation Items apply.

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