4.2-V to 42-V, 1.5-A ultra-small synchronous step-down converter


Product details


Vin (Min) (V) 3.6 Vin (Max) (V) 42 Vout (Min) (V) 3.3 Vout (Max) (V) 40 Iout (Max) (A) 1.5 Iq (Typ) (mA) 0.025 Iq (Typ) (uA) 25 Switching frequency (Min) (kHz) 400 Switching frequency (Max) (kHz) 2100 Operating temperature range (C) -40 to 125 Rating Automotive Regulated outputs (#) 1 open-in-new Find other Buck converters (integrated switch)

Package | Pins | Size

VQFN-HR (RNX) 12 6 mm² 3 x 2 open-in-new Find other Buck converters (integrated switch)


  • AEC-Q100-qualified for automotive applications:
    • Temperature grade 1: –40°C to +125°C, TA
  • Designed for automotive applications
    • Junction temperature range –40°C to +150°C
    • Protection features: thermal shutdown, input undervoltage lockout, cycle-by-cycle current limit, hiccup short-circuit protection
    • 0.4-V dropout with 1.5-A load (typical)
    • ±1.5% reference voltage tolerance
    • 5-V fixed-output, adjustable output voltage options
  • Suited for scalable power supplies
  • Integration reduces solution size and cost
    • Small, 2-mm × 3-mm VQFN package with wettable flanks
      • Few external components
    • Low power dissipation across load spectrum
      • 93% efficiency at 400 kHz (12VIN, 5VOUT, 1A)
      • Increased light load efficiency in PFM
      • Low operating quiescent current of 24 µA
    • Optimized for ultra low EMI requirements
      • Meets CISPR25 class 5 standard
      • Hotrod™ package minimizes switch node ringing
      • Parallel input path minimizes parasitic inductance
      • Spread spectrum reduces peak emissions

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    The LMR34215-Q1 regulator is an easy-to-use, synchronous, step-down DC/DC converter. With integrated high-side and low-side power MOSFETs, up to of output current is delivered over a wide input voltage range of 4.2 V to 42 V.

    The LMR34215-Q1 uses peak-current-mode control to provide optimal efficiency and output voltage accuracy. Precision enable gives flexibility by enabling a direct connection to the wide input voltage or precise control over device start-up and shutdown. The power-good flag, with built-in filtering and delay, offers a true indication of system status eliminating the requirement for an external supervisor.

    The LMR34215-Q1 is in a HotRod™ package which enables low EMI, higher efficiency, and the smallest package to die ratio. The device requires few external components and has a pinout designed for simple PCB layout. The small solution size and feature set of the LMR34215-Q1 are designed to simplify implementation for a wide range of end equipment.

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    Technical documentation

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    Type Title Date
    * Datasheet LMR34215-Q1 4.2-V to 42-V, 1.5-A Ultra-Small Synchronous Step-Down Converter datasheet (Rev. A) Oct. 03, 2019
    Selection guides Buck Converter Quick Reference Guide (Rev. A) Mar. 31, 2020
    Technical articles Optimizing flip-chip IC thermal performance in automotive designs Dec. 11, 2019
    User guides LMR34206 and LMR34215 EVM User's Guide Sep. 26, 2019
    User guides Automotive ADAS camera power supply reference design (Rev. A) Aug. 22, 2019
    Technical articles Minimize the impact of the MLCC shortage on your power application Mar. 29, 2019

    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 LMR34215FSC5EVM evaluation module (EVM) helps designers evaluate the operation and performance of the LMR34215-Q1 wide-input buck regulator. The LMR34215-Q1 is an easy-to-use synchronous step-down DC/DC converter capable of driving up to 1.5 A of load current from an input voltage of up to 42 V (...)
    • Integrated synchronous rectification
    • Tested against CISPR 25 Class 5 standards
    • Small solution size with low BOM count
    • Short minimum on-time
    document-generic User guide
    The LMR36015 evaluation module (EVM) is a fully assembled and tested circuit for evaluating the LMR36016 synchronous step-down converter.  The LMR36015 provides exceptional efficiency and accuracy in a very small solution size.
    • Inegrated synchronous rectification
    • Low operating quiescent current
    • High efficiency at light loads
    • Short minimum on-time

    Design tools & simulation

    SNVMBT1.ZIP (155 KB) - PSpice Model
    SNVMBT2.ZIP (161 KB) - PSpice Model
    SNVMBT7.ZIP (160 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
    • (...)

    CAD/CAE symbols

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    Ordering & quality

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