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) (uA) 25 Switching frequency (Min) (kHz) 400 Switching frequency (Max) (kHz) 2100 Features Enable, Forced PWM, Light Load Efficiency, Over Current Protection, Power Good, Synchronous Rectification 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
  • Functional Safety-Capable
  • Designed for automotive applications
    • Junction temperature range –40°C to +150°C
    • 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 (12 VIN, 5 VOUT, 1 A)
    • Increased light load efficiency in PFM
    • Low operating quiescent current of 24 µA
  • Optmized 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, 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.

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Technical documentation

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Type Title Date
* Data sheet LMR34215-Q1 4.2-V to 42-V, 1.5-A Ultra-Small Synchronous Step-Down Converter datasheet (Rev. B) Nov. 19, 2020
Selection guide Buck Converter Quick Reference Guide (Rev. B) Apr. 08, 2021
Functional safety information LMR34215-Q1 Functional Safety, FIT Rate, Failure Mode Distribution and Pin FMA Jan. 06, 2021
Technical article Powering levels of autonomy: a quick guide to DC/DC solutions for SAE autonomy levels Nov. 18, 2020
Technical article Optimizing flip-chip IC thermal performance in automotive designs Dec. 11, 2019
User guide LMR34206 and LMR34215 EVM User's Guide Sep. 26, 2019
User guide Automotive ADAS camera power supply reference design (Rev. A) Aug. 22, 2019
Technical article Minimize the impact of the MLCC shortage on your power application Mar. 29, 2019

Design & development

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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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VQFN-HR (RNX) 12 View options

Ordering & quality

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