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LMS3655

ACTIVE

5.5A, 36V Synchronous, 400kHz, Step-Down Converter

A newer version of this product is available

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Same functionality with different pin-out to the compared device
LM61460 ACTIVE 3-V to 36-V, 6-A, Low-EMI synchronous step-down converter Smaller solution size, higher efficiency and lower EMI.
TPSM63608 ACTIVE High-density, 36-V input, 1-V to 20-V output, 6-A power module in 7.5-mm x 6.5-mm HotRod™ QFN Smaller design with an integrated-inductor power module.

Product details

Vin (min) (V) 3.5 Vin (max) (V) 42 Vout (min) (V) 1 Vout (max) (V) 15 Iout (max) (A) 5.5 Iq (typ) (mA) 0.015 Switching frequency (min) (kHz) 250 Switching frequency (max) (kHz) 500 EMI features Low parasitic Hotrod packaging, Spread Spectrum Features Enable, Forced PWM, Frequency synchronization, Light Load Efficiency, Over Current Protection, Power good, Pre-Bias Start-Up, Spread Spectrum, Synchronous Rectification, Wettable flanks package Operating temperature range (°C) -40 to 125 Rating Catalog Regulated outputs (#) 1 Control mode current mode Duty cycle (max) (%) 98 Type Converter
Vin (min) (V) 3.5 Vin (max) (V) 42 Vout (min) (V) 1 Vout (max) (V) 15 Iout (max) (A) 5.5 Iq (typ) (mA) 0.015 Switching frequency (min) (kHz) 250 Switching frequency (max) (kHz) 500 EMI features Low parasitic Hotrod packaging, Spread Spectrum Features Enable, Forced PWM, Frequency synchronization, Light Load Efficiency, Over Current Protection, Power good, Pre-Bias Start-Up, Spread Spectrum, Synchronous Rectification, Wettable flanks package Operating temperature range (°C) -40 to 125 Rating Catalog Regulated outputs (#) 1 Control mode current mode Duty cycle (max) (%) 98 Type Converter
VQFN-HR (RNL) 22 20 mm² 5 x 4
  • 96% Peak Efficiency While Converting 12 V to 5 V
  • Low EMI and Switch Noise
    • Minimized Switch Node Ringing
    • Pseudo-Random Spread Spectrum
  • 400-kHz (±10%) Fixed Switching Frequency
  • –40°C to +150°C Junction Temperature Range
  • External Frequency Synchronization
  • RESET Output With Internal Filter and 3-ms Release Timer
  • Automatic Light Load Mode for Improved Efficiency
  • Pin-Selectable Forced PWM Mode
  • Built-In Compensation, Soft Start, Current Limit, Thermal Shutdown, and UVLO
  • 0.35-V Dropout With 3.5-A Load at 25°C (Typical)
  • 32-µA IQ_VIN: Quiescent Current at 3.3 VOUT and No Load (Typical)
  • 5.5-A Continuous Load Current
  • Adjustable Output Voltage (1 V to 20 V)
  • ±1.5% Reference Voltage Tolerance
  • 4-mm × 5-mm, 0.5-mm Pitch SON Package
  • 96% Peak Efficiency While Converting 12 V to 5 V
  • Low EMI and Switch Noise
    • Minimized Switch Node Ringing
    • Pseudo-Random Spread Spectrum
  • 400-kHz (±10%) Fixed Switching Frequency
  • –40°C to +150°C Junction Temperature Range
  • External Frequency Synchronization
  • RESET Output With Internal Filter and 3-ms Release Timer
  • Automatic Light Load Mode for Improved Efficiency
  • Pin-Selectable Forced PWM Mode
  • Built-In Compensation, Soft Start, Current Limit, Thermal Shutdown, and UVLO
  • 0.35-V Dropout With 3.5-A Load at 25°C (Typical)
  • 32-µA IQ_VIN: Quiescent Current at 3.3 VOUT and No Load (Typical)
  • 5.5-A Continuous Load Current
  • Adjustable Output Voltage (1 V to 20 V)
  • ±1.5% Reference Voltage Tolerance
  • 4-mm × 5-mm, 0.5-mm Pitch SON Package

The LMS3655 synchronous buck regulators are optimized for high performance applications, providing an adjustable output of 1 V to 20 V. Seamless transition between PWM and PFM modes, along with a low quiescent current, ensures high efficiency and superior transient responses at all loads.

Advanced high-speed circuitry allows the LMS3655 to regulate an input of 24 V to an output of 3.3 V at a fixed frequency of 400 kHz while also enabling a continuous load current of 5.5 A. An innovative frequency foldback architecture allows this device to regulate a 3.3-V output from an input voltage of only 3.5 V. The input voltage can range up to 36 V, with transient tolerance up to 42 V, easing input surge protection design.

An open-drain reset output, with built-in filtering and delay, provides a true indication of system status. This feature negates the requirement for an additional supervisory component, saving cost and board space.

The LMS3655 synchronous buck regulators are optimized for high performance applications, providing an adjustable output of 1 V to 20 V. Seamless transition between PWM and PFM modes, along with a low quiescent current, ensures high efficiency and superior transient responses at all loads.

Advanced high-speed circuitry allows the LMS3655 to regulate an input of 24 V to an output of 3.3 V at a fixed frequency of 400 kHz while also enabling a continuous load current of 5.5 A. An innovative frequency foldback architecture allows this device to regulate a 3.3-V output from an input voltage of only 3.5 V. The input voltage can range up to 36 V, with transient tolerance up to 42 V, easing input surge protection design.

An open-drain reset output, with built-in filtering and delay, provides a true indication of system status. This feature negates the requirement for an additional supervisory component, saving cost and board space.

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Technical documentation

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Type Title Date
* Data sheet LMS3655 5.5-A, 36-V Synchronous, 400-kHz DC-DC Step-Down Converter datasheet (Rev. B) PDF | HTML 01 Mar 2018
Selection guide Buck Converter Quick Reference Guide (Rev. B) 08 Apr 2021
EVM User's guide LMS36x5-Q1 EVM User's Guide (Rev. A) 13 Apr 2018
Technical article Powering up the performance of sensitive test and measurement systems PDF | HTML 17 Oct 2017
Application note Designing High Performance, Low-EMI, Automotive Power Supplies 30 Sep 2017

Design & development

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

Evaluation board

LMS3655AQEVM — LMS3655-Q1 5.5A, 5V Synchronous, 400kHz, Step-Down Converter Evaluation Module

The LMS3655AQEVM evaluation module (EVM) demonstrates the capabilities of the LMS3655 automotive integrated buck converter. For optimized EMI performance, the EVM has an EMI filter on the back side that assists with noise reduction. The user can choose to bypass that EMI filter (...)
User guide: PDF
Not available on TI.com
Evaluation board

LMS3655MQEVM — LMS3655-Q1 5.5A, 5V Synchronous, 400kHz, Step-Down Converter Evaluation Module

The LMS3655MQEVM evaluation module (EVM) demonstrates the capabilities of the LMS3655-Q1 automotive integrated buck converter. For optimized EMI performance, the LMS3655-Q1 has Spread Spectrum built in and the  EVM has an EMI filter on the back side that assists with noise reduction. The (...)
User guide: PDF
Not available on TI.com
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 (...)
Reference designs

PMP20249 — CISPR 25 Class 4 Rated Design for Dual Automotive USB Charger Reference Design

PMP20249 is an EMI optimized design for dual automotive USB charger system utilizing the LMS3635 and LMS3655 regulator ICs (400kHz fully-integrated synchronous buck for automotive application) and TPS2549 USB switch (TPS2549-Q1 automotive USB charging port controller with integrated power switch (...)
Test report: PDF
Schematic: PDF
Reference designs

PMP40269 — USB Type-C™ DFP 5V 1.5A + USB Type-A 5V 2.4A Car Charger Reference Design

PMP40269 is a dual port car charger reference design. It has a USB Type-C™ port and a USB type-A port. The USB Type-C port can provide 5V 1.5A to USB Type-C device. The type-A port can provide 5V 2.4A, it is also capable of compensating for the effects on voltage droop when a smartphone or (...)
Test report: PDF
Schematic: PDF
Package Pins Download
VQFN-HR (RNL) 22 View options

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