SNVS032E February   2000  – January 2016 LM2651


  1. Features
  2. Applications
  3. Description
  4. Revision History
  5. Pin Configuration and Functions
  6. Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Typical Characteristics
  7. Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
    4. 7.4 Device Functional Modes
  8. Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. Input Capacitor
        2. Inductor
        3. Output Capacitor
        4. Boost Capacitor
        5. Soft-Start Capacitor
        6. R1 and R2 (Programming Output Voltage)
        7. Compensation Components
        8. External Schottky Diode
      3. 8.2.3 Application Curves
  9. Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Community Resources
    2. 11.2 Trademarks
    3. 11.3 Electrostatic Discharge Caution
    4. 11.4 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

1 Features

  • Ultrahigh Efficiency up to 97%
  • High-Efficiency Over a 1.5-A to 1.5-mA Load Range
  • 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 Control
  • Input Undervoltage Lockout
  • Adjustable Soft-Start
  • Current Limit and Thermal Shutdown
  • 16-Pin TSSOP Package

2 Applications

  • Personal Digital Assistants (PDAs)
  • Computer Peripherals
  • Battery-Powered Devices
  • Handheld Scanners
  • High-Efficiency 5-V Conversion

3 Description

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.

Device Information(1)

LM2651 TSSOP (16) 5.00 mm × 4.40 mm
  1. For all available packages, see the orderable addendum at the end of the data sheet.

Typical Application

LM2651 10092501.gif