Product details


Vin (Min) (V) 4 Vin (Max) (V) 14 Vout (Min) (V) 3.3 Vout (Max) (V) 13 Iout (Max) (A) 1.5 Iq (Typ) (uA) 1600 Switching frequency (Min) (kHz) 255 Switching frequency (Max) (kHz) 345 Features UVLO Adjustable Operating temperature range (C) -40 to 125 Rating Catalog Regulated outputs (#) 1 open-in-new Find other Buck converters (integrated switch)

Package | Pins | Size

TSSOP (PW) 16 22 mm² 5 x 4.4 open-in-new Find other Buck converters (integrated switch)


  • Ultrahigh Efficiency up to 97%
  • High-Efficiency Over a 1.5-A to 1.5-mA Load
  • 4-V to 14-V Input Voltage Range
  • 1.8-V, 2.5-V, 3.3-V, or ADJ Output Voltage
  • Internal MOSFET Switch With Low RDS(on) of
    75 mΩ
  • 300-kHz Fixed Frequency Internal Oscillator
  • 7-µA Shutdown Current
  • Patented Current Sensing for Current Mode
  • Input Undervoltage Lockout
  • Adjustable Soft-Start
  • Current Limit and Thermal Shutdown
  • 16-Pin TSSOP Package

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The LM2651 switching regulator provides high-efficiency power conversion over a 100:1 load range (1.5 A to 15 mA). This feature makes the LM2651 an ideal fit in battery-powered applications that demand long battery life in both run and standby modes.

Synchronous rectification is used to achieve up to 97% efficiency. At light loads, the LM2651 enters a low power hysteretic or sleep mode to maintain high efficiency. In many applications, the efficiency still exceeds 80% at 15-mA load. A shutdown pin is available to disable the LM2651 and reduce the supply current to less than 10 µA.

The LM2651 contains a patented current sensing circuitry for current mode control. This feature eliminates the external current sensing resistor required by other current-mode DC-DC converters.

The LM2651 has a 300-kHz fixed frequency internal oscillator. The high oscillator frequency allows the use of extremely small, low-profile components.

A programmable soft-start feature limits current surges from the input power supply at start-up and provides a simple means of sequencing multiple power supplies.

Other protection features include input undervoltage lockout, current limiting, and thermal shutdown.

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Technical documentation

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Type Title Date
* Data sheet LM2651 1.5 A High-Efficiency Synchronous Switching Regulator datasheet (Rev. E) Nov. 03, 2015
Selection guide Buck Converter Quick Reference Guide (Rev. B) Apr. 08, 2021
Technical article Minimize the impact of the MLCC shortage on your power application Mar. 29, 2019
User guide LM2651 EVAL 1.5A High Efficiency Synch Switching Reg Eval Board (Rev. A) Apr. 24, 2013
User guide LM2651_3.3V_EVAL 1.5A High Eff Sync Switching Regulator Eval Board (Rev. C) Apr. 24, 2013

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document-generic User guide

1.5A High Efficiency Switching Regulator

  • Ultra high efficiency up to 97%.
  • High efficiency over a 1.5A to milliamperes load range
  • 4V to 14V input voltage range
  • 1.8V, 2.5V, 3.3V, or Adj output voltage
  • Internal MOSFET switch with low RDS(on) of 75mW
  • 300kHz fixed frequency internal oscillator
  • 7mA shutdown current
  • Patented current sensing for current (...)

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  • Leverages Cadence PSpice Technology
  • Preinstalled library with a suite of digital models to enable worst-case timing analysis
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  • Supports simultaneous analysis of multiple products
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TSSOP (PW) 16 View options

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