SIMPLE SWITCHER® 3.8-V to 36-V, 4-A step-down converter in SOIC-8 package


Product details


Vin (Min) (V) 3.8 Vin (Max) (V) 36 Vout (Min) (V) 1 Vout (Max) (V) 24 Iout (Max) (A) 4 Iq (Typ) (uA) 24 Switching frequency (Min) (kHz) 400 Switching frequency (Max) (kHz) 1000 Features Enable, Light Load Efficiency, Over Current Protection, Power Good, Pre-Bias Start-Up, Synchronous Rectification, Wettable Flanks Package Operating temperature range (C) -40 to 125 Rating Catalog Regulated outputs (#) 1 open-in-new Find other Buck converters (integrated switch)

Package | Pins | Size

HSOIC (DDA) 8 19 mm² 4.9 x 3.9 open-in-new Find other Buck converters (integrated switch)


  • Functional Safety-Capable
  • Configured for rugged industrial applications
    • Input voltage range: 3.8 V to 36 V
    • Output voltage range: 1 V to 24 V
    • Peak-current mode control
    • Junction temperature range: –40°C to +125°C
    • Ease-of-use SOIC package
  • Well-suited for scalable industrial power supplies
    • Pin compatible with:
    • 400-kHz and 1-MHz frequency
    • Integrated compensation helps reduce solution size, cost, and design complexity
  • High-efficiency solution
    • Peak efficiency > 95%
    • Low shutdown quiescent current of 5 µA
    • Low operating quiescent current of 24 µA
  • Flexible system interface
    • Power-good flag and precision enable
  • Create a custom design using the LMR33640 with the WEBENCH Power Designer
  • Use TPSM53604 module for faster time to market
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The LMR33640 SIMPLE SWITCHER regulator is an easy-to-use, synchronous, step-down DC/DC converter that delivers best-in-class efficiency for rugged industrial applications. The LMR33640 drives up to 4 A of load current from an input of up to 36 V. The LMR33640 provides high light-load efficiency and output accuracy. Features such as a power-good flag and precision enable provide both flexible and easy-to-use solutions for a wide range of applications. The LMR33640 automatically folds back frequency at light load to improve efficiency. Protection features include thermal shutdown, input undervoltage lockout, cycle-by-cycle current limit, and hiccup short-circuit protection. Integration and internal compensation eliminates many external components and provides a pinout designed for a simple PCB layout. The feature set of the device is designed to simplify implementation for a wide range of end equipment. The LMR33640 is pin-to-pin compatible with the LMR33610, LMR33620, LMR33630 (36 V, 1 A/2, A/3 A), LMR36510 (65 V, 1 A), and LMR36520 (65 V, 2 A), completing the family of scalable SIMPLE SWITCHER power supplies. This minimizes the cost and effort associated with board layout modifications. The LMR33640 is available in an 8-pin HSOIC package.

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Technical documentation

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Type Title Date
* Data sheet LMR33640 SIMPLE SWITCHER 3.8-V to 36-V, 4-A Synchronous Step-down Converter datasheet (Rev. C) Nov. 24, 2020
Functional safety information LMR336x0 Functional Safety, FIT Rate, FMD and Pin FMA (Rev. A) Mar. 02, 2021
Application note Working with Inverting Buck-Boost Converters (Rev. A) May 14, 2020
Technical article 3 tips when designing a power stage for servo and AC drives Nov. 20, 2019
User guide LMR33640EVM User's Guide Nov. 01, 2019
Technical article Minimize the impact of the MLCC shortage on your power application Mar. 29, 2019
Technical article How to increase system reliability and simplify design using DC/DC converters Jun. 13, 2016

Design & development

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Hardware development

document-generic User guide
The LMR33640 evaluation module (EVM) is a fully assembled and tested circuit for evaluating the LMR33640ADDA synchronous step-down converer.
  • Integrated synchronous rectification
  • Low operating quiescent current
  • High light load efficiency
  • Short minimum on-time

Design tools & simulation

SNVMBV0.ZIP (175 KB) - PSpice Model
SNVMBV1.ZIP (172 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
  • (...)
SNVR484.ZIP (938 KB)

CAD/CAE symbols

Package Pins Download
SO PowerPAD (DDA) 8 View options

Ordering & quality

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  • Qualification summary
  • Ongoing reliability monitoring

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