Product details


Vin (Min) (V) 3.5 Vin (Max) (V) 42 Vout (Min) (V) 1 Vout (Max) (V) 15 Iout (Max) (A) 3.5 Iq (Typ) (uA) 15 Switching frequency (Min) (kHz) 250 Switching frequency (Max) (kHz) 500 Features Enable, 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 open-in-new Find other Buck converters (integrated switch)

Package | Pins | Size

VQFN-HR (RNL) 22 VQFN-HR (RNL) 22 20 mm² 4 x 5 open-in-new Find other Buck converters (integrated switch)


  • 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
open-in-new Find other Buck converters (integrated switch)


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.

open-in-new Find other Buck converters (integrated switch)

Technical documentation

star = Top documentation for this product selected by TI
No results found. Please clear your search and try again.
View all 7
Type Title Date
* Data sheet LMS3635-Q1 3.5-A, LMS3655-Q1 5.5-A, 36-V Synchronous, 400-kHz Step-Down Converter datasheet (Rev. C) Aug. 01, 2021
Selection guide Buck Converter Quick Reference Guide (Rev. B) Apr. 08, 2021
Analog design journal Clutter‐free power supplies for RF converters in radar applications (Part 1)  Mar. 18, 2021
Technical article Optimizing flip-chip IC thermal performance in automotive designs Dec. 11, 2019
Technical article Minimize the impact of the MLCC shortage on your power application Mar. 29, 2019
User guide LMS36x5-Q1 EVM User's Guide (Rev. A) Apr. 13, 2018
Application note Designing High Performance, Low-EMI, Automotive Power Supplies Sep. 30, 2017

Design & development

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

Hardware development

document-generic User guide
The LMS3635MQEVM evaluation module (EVM) demonstrates the capabilities of the LMS3635-Q1 automotive integrated buck converter. For optimized EMI performance, the LMS3635-Q1 has Spread Spectrum built in and the  EVM has an EMI filter on the back side that assists with noise reduction. The user (...)
  • High Efficiency with 400kHz and Auto Light Mode PFM/PWM or Forced PWM Mode operation
  • /RESET Power Good output with 3ms delay on timer
  • External Frequency Synchronisation Input
  • Low EMI
  • Fully Synchronous with integrated HS and LS FET

Design tools & simulation

SNAM207.ZIP (7 KB) - PSpice Model
SNAM208.ZIP (123 KB) - PSpice Model
SNAM209.ZIP (122 KB) - PSpice Model
SNAM210.ZIP (8 KB) - PSpice Model
SNAM211.ZIP (8 KB) - PSpice Model
SNAM212.ZIP (106 KB) - PSpice Model
PSpice® for TI design and simulation tool
PSPICE-FOR-TI — 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 (...)
  • Leverages Cadence PSpice Technology
  • Preinstalled library with a suite of digital models to enable worst-case timing analysis
  • Dynamic updates ensure you have access to most current device models
  • Optimized for simulation speed without loss of accuracy
  • Supports simultaneous analysis of multiple products
  • (...)

Reference designs

CISPR 25 Class 4 Rated Design for Dual Automotive USB Charger Reference Design
PMP20249 — 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 (...)
document-generic Schematic
Reference Design Maximizing Signal Dynamic Range for True 10 Vpp Differential Input to 20 bit ADC
TIDA-01057 — This reference design is designed for high performance data acquisition(DAQ) systems to improve the dynamic range of 20 bit differential input ADCs. Many DAQ systems require the measurement capability at a wide FSR (Full Scale Range) in order to obtain sufficient signal dynamic range. Many earlier (...)
document-generic Schematic
20-bit 1MSPS DAQ Reference Design Optimizing Power Supply Efficiency While Minimizing EMI
TIDA-01056 — This reference design for high performance data acquisition (DAQ) systems optimizes power stage in order to reduce power consumption and minimize the effect of EMI from switching regulator by using LMS3635-Q1 buck converter.  This reference designs yields 7.2% efficiency improvement at most (...)
document-generic Schematic
Dual USB Type-C™ 1.5A DFPs Car Charger Reference Design
PMP40270 — PMP40270 is a dual USB type-C DFPs reference design, as a cigar lighter adapter. It has a high effieicny DCDC converter LMS3635  inside, combined with a low cost USB type-C source controller TPS25821 for each port. Full voltage range of a 12V car battery, as well as the transistion voltage up (...)
document-generic Schematic
Automotive USB Type-C™ DFP 5V 3A Charger with Linear Droop Compensation Reference Design
PMP40268 — The PMP40268 is a USB Type-C™ DFP car charger reference design which provides 5V 3A for USB Type-C™ device. The design includes a synchronous step-down converter LMS3635, and high integrated USB Type-C™ controller and power switch TPS25810. The design is capable of compensating for (...)
document-generic Schematic
Automotive Passive Media Hub Reference Design With Charging and Enhanced Data Path Performance
TIDA-01432 — This automotive reference design demonstrates a unique approach for media ports that require data transfers. This design has the capability to support USB 2.0 through a 15-W USB Type-C™ port. Customers can accelerate their media port systems by taking advantage of a complete reference design (...)
document-generic Schematic
Compact 27W USB Type C Power Delivery Reference Design
PMP20807 — The PMP20807 reference design is a USB Type C power delivery solution configurable for 5V or 9V output. This compact reference design has a total solution size of 44mm x 18mm x 7.8mm. The low quiescent current capability of LMS3635A and TPS25740A  minimizes the amount of necessary input power (...)
document-generic Schematic

CAD/CAE symbols

Package Pins Download
VQFN-HR (RNL) 22 View options

Ordering & quality

Information included:
  • RoHS
  • Device marking
  • Lead finish/Ball material
  • MSL rating/Peak reflow
  • MTBF/FIT estimates
  • Material content
  • Qualification summary
  • Ongoing reliability monitoring

Recommended products may have parameters, evaluation modules or reference designs related to this TI product.

Support & training

TI E2E™ forums with technical support from TI engineers

Content is provided "as is" by TI and community contributors and does not constitute TI specifications. See terms of use.

If you have questions about quality, packaging or ordering TI products, see TI support. ​​​​​​​​​​​​​​