LMS3655-Q1 3.5A /5.5A, 36V Synchronous, 400kHz, Step-Down Converter | TI.com

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3.5A /5.5A, 36V Synchronous, 400kHz, Step-Down Converter


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The LMS3635-Q1 and LMS3655-Q1 synchronous buck regulators are optimized for high performance applications, providing an output voltage of 3.3 V, 5 V, or an adjustable output of 1 V to 20 V. Seamless transition between PWM and PFM modes, along with a low quiescent current, ensures high efficiency and superior transient responses at all loads.

Advanced high-speed circuitry allows the LMS3655-Q1 to regulate an input of 24 V to an output of 3.3 V at a fixed frequency of 400 kHz while also enabling a continuous load current of 5.5 A. An innovative frequency foldback architecture allows this device to regulate a 3.3-V output from an input voltage of only 3.5 V. The input voltage can range up to 36 V, with transient tolerance up to 42 V, easing input surge protection design.

An open-drain reset output, with built-in filtering and delay, provides a true indication of system status. This feature negates the requirement for an additional supervisory component, saving cost and board space.


  • AEC-Q100 Qualified for Automotive Applications
    • Device Temperature Grade 1: –40°C to +125°C Ambient Operating Temperature
    • Device HBM Classification Level 2
    • Device CDM Classification Level C6
  • 96% Peak Efficiency While Converting 12 V to 5 V
  • Low EMI and Minimized Switch Node Ringing
  • 400-kHz (±10%) Fixed Switching Frequency
  • –40°C to +150°C Junction Temperature Range
  • External Frequency Synchronization
  • RESET Output With Internal Filter and 3-ms Release Timer
  • Automatic Light Load Mode for Improved Efficiency
  • Pin-Selectable Forced PWM Mode
  • Built-In Compensation, Soft Start, Current Limit, Thermal Shutdown, and UVLO
  • 0.35-V Dropout With 3.5-A Load at 25°C (Typical)
  • 18-µA IQ_VIN: Quiescent Current at 3.3 VOUT and No Load (Typical)
  • Output Voltage: 5 V, 3.3 V, and ADJ (1 V to 20 V)
  • ±1.5% Reference Voltage Tolerance

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WEBENCH® Designer LMS3655-Q1

  Min   Max Range
Vin  V 3.8 to 36.0V
Vout  V 3.3 to 15V
Iout  A ≤ 5.5A
Ambient Temp  °C -40 to 125°C


Compare all products in Buck converters (integrated switch) Email Download to Excel
Part number Order Vin (Min) (V) Vin (Max) (V) Vout (Min) (V) Vout (Max) (V) Iout (Max) (A) Regulated outputs (#) Switching frequency (Min) (kHz) Switching frequency (Max) (kHz) Iq (Typ) (mA) Features Control mode Duty cycle (Max) (%) Operating temperature range (C) Rating Package Group Type Package size: mm2:W x L (PKG)
LMS3655-Q1 Order now 3.5     42     1     15     5.5     1     250     500     0.015     Enable
Forced PWM
Frequency Synchronization
Light Load Efficiency
Over Current Protection
Power Good
Pre-Bias Start-Up
Spread Spectrum
Synchronous Rectification
Wettable Flanks Package
Fixed Output
Soft Start Fixed    
Current Mode     98     -40 to 150     Automotive     VQFN-HR | 22     Converter     22VQFN-HR: 20 mm2: 4 x 5 (VQFN-HR | 22)