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LM65645-Q1

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Automotive, 4.5A, 3V to 65V buck converter optimized for power density and low EMI

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Data sheet

LM65645-Q1

ACTIVE
Data sheet Order now

Product details

Rating Automotive Topology Buck Iout (max) (A) 4.5 Vin (max) (V) 65 Vin (min) (V) 3 Vout (max) (V) 40 Vout (min) (V) 0.8 Features Adjustable switching frequency, Auto Mode, Enable, Fixed Output, Forced PWM, Frequency synchronization, Overcurrent protection, Power good, Spread Spectrum, Thermal shutdown, UVLO adjustable EMI features Low parasitic Hotrod packaging, Spread Spectrum Control mode current mode Switching frequency (min) (kHz) 360 Switching frequency (max) (kHz) 2200 TI functional safety category Functional Safety-Capable Operating temperature range (°C) -40 to 150 Duty cycle (max) (%) 98 Type Converter
Rating Automotive Topology Buck Iout (max) (A) 4.5 Vin (max) (V) 65 Vin (min) (V) 3 Vout (max) (V) 40 Vout (min) (V) 0.8 Features Adjustable switching frequency, Auto Mode, Enable, Fixed Output, Forced PWM, Frequency synchronization, Overcurrent protection, Power good, Spread Spectrum, Thermal shutdown, UVLO adjustable EMI features Low parasitic Hotrod packaging, Spread Spectrum Control mode current mode Switching frequency (min) (kHz) 360 Switching frequency (max) (kHz) 2200 TI functional safety category Functional Safety-Capable Operating temperature range (°C) -40 to 150 Duty cycle (max) (%) 98 Type Converter
WQFN-FCRLF (RZT) 20 9.36 mm² 3.6 x 2.6
  • AEC-Q100 qualified for automotive applications:
    • Temperature grade 1: –40°C to +125°C, TA
  • Wide input voltage range: 3V to 65V (70V transient < 100ms)
    • Meets LV148 / ISO21780 requirements
  • Designed for low EMI requirements
    • Facilitates CISPR 25 class 5 compliance
    • Mode pin configurable ±5% or ±10% dual-random spread spectrum reducing peak emissions
    • Enhanced HotRod™ QFN package with symmetrical pinout
    • Switching frequency from 300kHz to 2.2MHz
    • Pin-configurable AUTO or FPWM operation
    • Internal compensation, current limit, and TSD
  • Low minimum on time: 40ns (maximum)
    • Enables 36VIN to 3.3VOUT conversion at 2.2MHz
  • High-efficiency power conversion at all loads
    • > 94% peak efficiency at 24VIN, 5VOUT, 400kHz
    • 2.5µA switching input current at no load
  • High power density
    • 3.6mm × 2.6mm, wettable flank, 20-pin package
    • Pin compatible with 36V LM654x0-Q1
    • ϴJA = 24.0°C/W (LM65645-Q1EVM)
  • Create a custom design using the LM656x5-Q1 with the WEBENCH Power Designer
  • AEC-Q100 qualified for automotive applications:
    • Temperature grade 1: –40°C to +125°C, TA
  • Wide input voltage range: 3V to 65V (70V transient < 100ms)
    • Meets LV148 / ISO21780 requirements
  • Designed for low EMI requirements
    • Facilitates CISPR 25 class 5 compliance
    • Mode pin configurable ±5% or ±10% dual-random spread spectrum reducing peak emissions
    • Enhanced HotRod™ QFN package with symmetrical pinout
    • Switching frequency from 300kHz to 2.2MHz
    • Pin-configurable AUTO or FPWM operation
    • Internal compensation, current limit, and TSD
  • Low minimum on time: 40ns (maximum)
    • Enables 36VIN to 3.3VOUT conversion at 2.2MHz
  • High-efficiency power conversion at all loads
    • > 94% peak efficiency at 24VIN, 5VOUT, 400kHz
    • 2.5µA switching input current at no load
  • High power density
    • 3.6mm × 2.6mm, wettable flank, 20-pin package
    • Pin compatible with 36V LM654x0-Q1
    • ϴJA = 24.0°C/W (LM65645-Q1EVM)
  • Create a custom design using the LM656x5-Q1 with the WEBENCH Power Designer

The LM656x5-Q1 are a family of automotive buck converters designed for high efficiency, high-power density, and ultra-low electromagnetic interference (EMI). The converters operate over a wide input voltage range of 3V to 65V (70V transient < 100ms), reducing the need for external input surge protection. The LM656x5-Q1 comes with pin selectable fixed output voltages of 3.3V and 5V or in adjustable configuration. The low EMI operation is enabled with minimized loop inductance and optimized switch node slew rate. A pin-selectable ±5% or ±10% dual-random spread spectrum (DRSS) significantly reduces peak emissions through a combination of triangular and pseudo-random modulation while keeping output voltage ripple very low. The current-mode control architecture with a 30ns typical minimum on-time allows high conversion ratios at high frequencies coupled with a fast transient response and excellent load and line regulation.

The LM656x5-Q1 are a family of automotive buck converters designed for high efficiency, high-power density, and ultra-low electromagnetic interference (EMI). The converters operate over a wide input voltage range of 3V to 65V (70V transient < 100ms), reducing the need for external input surge protection. The LM656x5-Q1 comes with pin selectable fixed output voltages of 3.3V and 5V or in adjustable configuration. The low EMI operation is enabled with minimized loop inductance and optimized switch node slew rate. A pin-selectable ±5% or ±10% dual-random spread spectrum (DRSS) significantly reduces peak emissions through a combination of triangular and pseudo-random modulation while keeping output voltage ripple very low. The current-mode control architecture with a 30ns typical minimum on-time allows high conversion ratios at high frequencies coupled with a fast transient response and excellent load and line regulation.
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* Data sheet LM656x5-Q1 High-Performance, 3V to 65V , Pin Compatible, 2.5A, 3.5A, 4.5A, Automotive , Low EMI, Synchronous Buck Converters datasheet (Rev. A) PDF | HTML 27 May 2025
Application note Controller to Converter – Design Considerations for 24V and 48V Systems PDF | HTML 02 Oct 2024
Application note Reducing Conducted EMI in a Buck Converter for 48 V Automotive Applications PDF | HTML 13 Dec 2023
E-book An Engineer’s Guide to Low EMI in DC/DC Regulators 21 Apr 2021
Technical article Using DC/DCs buck converters to power modern safety features in commercial vehicle PDF | HTML 27 Jul 2020
Technical article How to meet European Commission ADAS requirements with TI DC/DC converters PDF | HTML 09 May 2019
Technical article Top three qualities to consider when designing a video doorbell power supply PDF | HTML 25 Sep 2018
White paper An overview of radiated EMI specifications for power supplies 05 Jun 2018
Technical article Effects of IC package on EMI performance PDF | HTML 22 May 2018
White paper An overview of conducted EMI specifications for power supplies 01 Feb 2018

Design & development

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Evaluation board

LM65645EVM — LM65645 evaluation module

The LM65645 evaluation module (EVM) helps designers evaluate the operation and performance of the LM65645 family of wide input voltage buck converters. The LM65645 family are easy-to-use synchronous step-down converters capable of supplying up to 2.5A, 3.5A or 4.5A of load current from an input (...)
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Simulation model

LM6x625 Transient SPICE Model

SNVMCE9.ZIP (2204 KB) - TISpice Model
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Calculation tool

LM656X5-CALC — LM656x5 Quick start design calculator

Design calculator for LM656x5 family of converters
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AC/DC & DC/DC converters (integrated FET)
  • LM65645-Q1 — Automotive, 4.5A, 3V to 65V buck converter optimized for power density and low EMI
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WQFN-FCRLF (RZT) 20 Ultra Librarian
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