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LM65645
  • LM65645
  • LM65645

LM65645

ACTIVE

3V to 65V, 4.5A synchronous step-down converter optimized for power density and low EMI

Texas Instruments LM65645 Product Info

1 April 2026 0

Parameters

Rating

Catalog

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

Operating temperature range (°C)

-40 to 150

Duty cycle (max) (%)

98

TI functional safety category

Functional Safety-Capable

Package

WQFN-FCRLF (RZT)-20-9.36 mm² 3.6 x 2.6

Features

  • Wide input voltage range: 3V to 65V (70V transient < 100ms)
    • Meets LV148 / ISO21780 requirements
  • Designed for low EMI requirements
    • Facilitates CISPR 11 class B 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 4/6/8A LM654x0-Q1
    • ϴJA = 24.0°C/W (LM65645EVM)
  • Create a custom design using the LM656x5 with the WEBENCH Power Designer
  • Wide input voltage range: 3V to 65V (70V transient < 100ms)
    • Meets LV148 / ISO21780 requirements
  • Designed for low EMI requirements
    • Facilitates CISPR 11 class B 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 4/6/8A LM654x0-Q1
    • ϴJA = 24.0°C/W (LM65645EVM)
  • Create a custom design using the LM656x5 with the WEBENCH Power Designer

Description

The LM656x5 are a family of 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 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 are a family of 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 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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