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LMR66430

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36V, 3A synchronous step-down converter with 1.5uA IQ and low EMI

Product details

Rating Catalog Operating temperature range (°C) -40 to 150 TI functional safety category Functional Safety-Capable Topology Buck Type Converter Iout (max) (A) 3 Vin (min) (V) 3 Vin (max) (V) 36 Switching frequency (min) (kHz) 200 Switching frequency (max) (kHz) 2200 Features Enable, Fixed Output, Forced PWM, Frequency synchronization, Light Load Efficiency, Low Noise, Over Current Protection, Power good, Soft Start Fixed, Spread Spectrum, Synchronous Rectification, UVLO adjustable, Wettable flanks package Control mode current mode Vout (min) (V) 1 Vout (max) (V) 35 Iq (typ) (µA) 1.5 Duty cycle (max) (%) 98
Rating Catalog Operating temperature range (°C) -40 to 150 TI functional safety category Functional Safety-Capable Topology Buck Type Converter Iout (max) (A) 3 Vin (min) (V) 3 Vin (max) (V) 36 Switching frequency (min) (kHz) 200 Switching frequency (max) (kHz) 2200 Features Enable, Fixed Output, Forced PWM, Frequency synchronization, Light Load Efficiency, Low Noise, Over Current Protection, Power good, Soft Start Fixed, Spread Spectrum, Synchronous Rectification, UVLO adjustable, Wettable flanks package Control mode current mode Vout (min) (V) 1 Vout (max) (V) 35 Iq (typ) (µA) 1.5 Duty cycle (max) (%) 98
VQFN-FCRLF (RXB) 14 6.76 mm² 2.6 x 2.6
  • Functional Safety-Capable
  • Designed for industrial applications:
    • Junction temperature range –40°C to +150°C
    • NC pin between critical pins for better reliability
    • Best in-class pin FMEA
    • Input transient protection up to 42 V
    • Wide input voltage range after start-up: 2.7 V (falling threshold) to 36 V
    • Adjustable output up to 95% of VIN, 3.3-V, and 5-V fixed VOUT options available
  • Optimized for low EMI requirements:
    • Dual random spread spectrum reduces peak emissions
    • Enhanced HotRod™ QFN package minimizes switch node ringing
  • Greater than 85% efficiency at 1 mA
  • Miniature design size and low component cost:
    • 2.6-mm × 2.6-mm enhanced HotRod QFN package with wettable flanks
    • Internal control loop compensation
  • Functional Safety-Capable
  • Designed for industrial applications:
    • Junction temperature range –40°C to +150°C
    • NC pin between critical pins for better reliability
    • Best in-class pin FMEA
    • Input transient protection up to 42 V
    • Wide input voltage range after start-up: 2.7 V (falling threshold) to 36 V
    • Adjustable output up to 95% of VIN, 3.3-V, and 5-V fixed VOUT options available
  • Optimized for low EMI requirements:
    • Dual random spread spectrum reduces peak emissions
    • Enhanced HotRod™ QFN package minimizes switch node ringing
  • Greater than 85% efficiency at 1 mA
  • Miniature design size and low component cost:
    • 2.6-mm × 2.6-mm enhanced HotRod QFN package with wettable flanks
    • Internal control loop compensation

The LMR664x0 is a small 36-V, 3-A (available in 2-A and 1-A variants) synchronous step-down DC/DC converter in an enhanced HotRod QFN package. This easy-to-use converter supports a wide input voltage range of 2.7 V to 36 V (after start-up or after operating) with transients up to 42 V.

The LMR664x0 is specifically designed to meet low standby power requirements for always-on, industrial applications. Auto mode enables frequency foldback when operating at light loads, allowing an unloaded typical current consumption of 1.5 µA at 13.5 VIN and high light load efficiency. A seamless transition between PWM and PFM modes along with very low MOSFET ON resistances makes sure there is exceptional efficiency across the entire load range. The control architecture (peak current mode) and feature set are optimized for an ultra-small design size with minimal output capacitance. The device minimizes input filter size by using dual-random spread spectrum (DRSS), a low-EMI enhanced HotRod QFN package, and an optimized pin-out. The MODE/SYNC and RT pin variants can be used to set or synchronize the frequency to avoid noise sensitive frequency bands. There are NC pins between critical high voltage pins, reducing potential failures (optimal pin FMEA). The rich feature set of the LMR664x0 is designed to simplify implementation for a wide range of industrial end equipment.

The LMR664x0 is a small 36-V, 3-A (available in 2-A and 1-A variants) synchronous step-down DC/DC converter in an enhanced HotRod QFN package. This easy-to-use converter supports a wide input voltage range of 2.7 V to 36 V (after start-up or after operating) with transients up to 42 V.

The LMR664x0 is specifically designed to meet low standby power requirements for always-on, industrial applications. Auto mode enables frequency foldback when operating at light loads, allowing an unloaded typical current consumption of 1.5 µA at 13.5 VIN and high light load efficiency. A seamless transition between PWM and PFM modes along with very low MOSFET ON resistances makes sure there is exceptional efficiency across the entire load range. The control architecture (peak current mode) and feature set are optimized for an ultra-small design size with minimal output capacitance. The device minimizes input filter size by using dual-random spread spectrum (DRSS), a low-EMI enhanced HotRod QFN package, and an optimized pin-out. The MODE/SYNC and RT pin variants can be used to set or synchronize the frequency to avoid noise sensitive frequency bands. There are NC pins between critical high voltage pins, reducing potential failures (optimal pin FMEA). The rich feature set of the LMR664x0 is designed to simplify implementation for a wide range of industrial end equipment.

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Technical documentation

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* Data sheet LMR664x0 36-V, 1-A, 2-A, and 3-A, Ultra-Small, Synchronous Step-Down Converter datasheet PDF | HTML 08 Dec 2023
Functional safety information LMR66430, LMR66430-Q1 Functional Safety FIT Rate, FMD and Pin FMA PDF | HTML 17 Nov 2023
Application brief Step-Down Converter Capacitor Integration Reducing Effort for CISPR 25 Class 5 Compliance PDF | HTML 18 Jan 2023

Design & development

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Evaluation board

LMR66430-2EVM — LMR66430 evaluation module for 36-V, 3-A synchronous buck converter with 2-Mhz frequency

The LMR66430-2 evaluation module (EVM) is a platform for the evaluation of the LMR66430 buck converter by containing several jumpers and test points to configure the device on the fly and test out its various features. In addition to evaluating the electrical performance of the LMR66430, this EVM (...)

User guide: PDF | HTML
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Design tool

LMR66430-2EVM Design Files

SNVR531.ZIP (4362 KB)
Package Pins CAD symbols, footprints & 3D models
VQFN-FCRLF (RXB) 14 Ultra Librarian

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