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) (uA) 15 Switching frequency (Min) (kHz) 250 Switching frequency (Max) (kHz) 500 Features Enable, Fixed Output, Forced PWM, Frequency Synchronization, Light Load Efficiency, Over Current Protection, Power Good, Pre-Bias Start-Up, Soft Start Fixed, Spread Spectrum, Synchronous Rectification, Wettable Flanks Package Operating temperature range (C) -40 to 150 Rating Automotive Regulated outputs (#) 1
Vin (Min) (V) 3.5 Vin (Max) (V) 42 Vout (Min) (V) 1 Vout (Max) (V) 15 Iout (Max) (A) 5.5 Iq (Typ) (uA) 15 Switching frequency (Min) (kHz) 250 Switching frequency (Max) (kHz) 500 Features Enable, Fixed Output, Forced PWM, Frequency Synchronization, Light Load Efficiency, Over Current Protection, Power Good, Pre-Bias Start-Up, Soft Start Fixed, Spread Spectrum, Synchronous Rectification, Wettable Flanks Package Operating temperature range (C) -40 to 150 Rating Automotive Regulated outputs (#) 1
VQFN-HR (RNL) 22 20 mm² 4 x 5
  • AEC-Q100-qualified for automotive applications
    • Device temperature grade 1: –40°C to +125°C ambient operating temperature
    • Device HBM classification level 2
    • Device CDM classification level C6
  • 96% Peak efficiency while converting 12 V to 5 V
  • Low EMI and minimized switch node ringing
  • 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)
  • 18-µA IQ_VIN: quiescent current at 3.3 VOUT and no load (typical)
  • Output voltage: 5 V, 3.3 V, and ADJ (1 V to 20 V)
  • ±1.5% reference voltage tolerance
  • Create a custom design using the LMS3655-Q1 with the WEBENCH Power Designer
  • AEC-Q100-qualified for automotive applications
    • Device temperature grade 1: –40°C to +125°C ambient operating temperature
    • Device HBM classification level 2
    • Device CDM classification level C6
  • 96% Peak efficiency while converting 12 V to 5 V
  • Low EMI and minimized switch node ringing
  • 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)
  • 18-µA IQ_VIN: quiescent current at 3.3 VOUT and no load (typical)
  • Output voltage: 5 V, 3.3 V, and ADJ (1 V to 20 V)
  • ±1.5% reference voltage tolerance
  • Create a custom design using the LMS3655-Q1 with the WEBENCH Power Designer

The LMS3635-Q1 and LMS3655-Q1 synchronous buck regulators are optimized for high performance applications, providing an output voltage of 3.3 V, 5 V, or 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-Q1 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 LMS3635-Q1 and LMS3655-Q1 synchronous buck regulators are optimized for high performance applications, providing an output voltage of 3.3 V, 5 V, or 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-Q1 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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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 using  (...)
Out of stock 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 (...)
In stock
Limit: 5
Evaluation board

LMS3655NQEVM — LMS3655-Q1 5.5A, 3.3V Synchronous, 400kHz Step-Down Converter Evaluation Module

The LMS3655NQEVM 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 (...)
In stock
Limit: 5
Simulation model

LMS36555-Q1 PSpice Transient Model

SNAM213.ZIP (108 KB) - PSpice Model
Simulation model

LMS36555-Q1 Unencrypted PSpice Transient Model

SNAM214.ZIP (7 KB) - PSpice Model
Simulation model

LMS3655A-Q1 Unencrypted PSpice Transient Model

SNAM215.ZIP (7 KB) - PSpice Model
Simulation model

LMS3655A-Q1 PSpice Transient Model

SNAM216.ZIP (157 KB) - PSpice Model
Simulation model

LMS36553-Q1 PSpice Transient Model

SNAM217.ZIP (105 KB) - PSpice Model
Simulation model

LMS36553-Q1 Unencrypted PSpice Transient Model

SNAM218.ZIP (7 KB) - PSpice Model
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 (...)
Reference designs

TIDA-01388 — CISPR 25 Class 5 Rated Dual Automotive USB Charger Reference Design With Full Front End Protection

TIDA-01388 is a 21 W dual automotive USB charger solution featuring complete front end protection with small size. The system can clamp fast high-voltage electrical transients and maintain operation through these events. It can also properly respond to a reverse battery polarity event and shut down (...)
Reference designs

TIDA-01253 — CISPR 25 Class 4 Automotive Dual Remote and Local USB Port Reference Design

This automotive media port design allows customers to accelerate media port systems by taking advantage of a complete reference design comprising analog AEC-100-qualified integrated circuits (ICs). The reference design is specified for automotive media ports that require both local-port and (...)
Reference designs

TIDA-01524 — Automotive High Efficiency Power Front End and Multi-Phase Processor Supply Reference Design

This processor supply reference design is an automotive power solution for use in highperformance, single-core-voltage application processors in advanced driver assistance systems (ADASs). This design can support core supply currents up to 10 A at 0.9 V. The design can also operate with a wide input (...)
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