SNVS008L September   1998  – June 2016 LM2671

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Description (continued)
  6. 6 Pin Configuration and Functions
  7. 7 Specifications
    1. 7.1  Absolute Maximum Ratings
    2. 7.2  ESD Ratings
    3. 7.3  Recommended Operating Conditions
    4. 7.4  Thermal Information
    5. 7.5  Electrical Characteristics - 3.3 V
    6. 7.6  Electrical Characteristics - 5 V
    7. 7.7  Electrical Characteristics - 12 V
    8. 7.8  Electrical Characteristics - Adjustable
    9. 7.9  Electrical Characteristics - All Output Voltage Versions
    10. 7.10 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Switch Output
      2. 8.3.2 Input
      3. 8.3.3 C Boost
      4. 8.3.4 Ground
      5. 8.3.5 Sync
      6. 8.3.6 Feedback
      7. 8.3.7 ON/OFF
    4. 8.4 Device Functional Modes
      1. 8.4.1 Shutdown Mode
      2. 8.4.2 Active Mode
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Applications
      1. 9.2.1 Fixed Output Voltage Version
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
          1. 9.2.1.2.1 Inductor Selection (L1)
          2. 9.2.1.2.2 Output Capacitor Selection (COUT)
          3. 9.2.1.2.3 Catch Diode Selection (D1)
          4. 9.2.1.2.4 Input Capacitor (CIN)
          5. 9.2.1.2.5 Boost Capacitor (CB)
          6. 9.2.1.2.6 Soft-Start Capacitor (CSS) - Optional
          7. 9.2.1.2.7 Frequency Synchronization (optional)
        3. 9.2.1.3 Application Curves
      2. 9.2.2 Adjustable Output Voltage Version
        1. 9.2.2.1 Design Requirements
        2. 9.2.2.2 Detailed Design Procedure
          1. 9.2.2.2.1 Programming Output Voltage
          2. 9.2.2.2.2 Inductor Selection (L1)
          3. 9.2.2.2.3 Output Capacitor Selection (COUT)
          4. 9.2.2.2.4 Catch Diode Selection (D1)
          5. 9.2.2.2.5 Input Capacitor (CIN)
          6. 9.2.2.2.6 Boost Capacitor (CB)
        3. 9.2.2.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Examples
  12. 12Device and Documentation Support
    1. 12.1 Documentation Support
      1. 12.1.1 Related Documentation
    2. 12.2 Receiving Notification of Documentation Updates
    3. 12.3 Community Resources
    4. 12.4 Trademarks
    5. 12.5 Electrostatic Discharge Caution
    6. 12.6 Glossary
  13. 13Mechanical, Packaging, and Orderable Information
    1. 13.1 DAP (WSON Package)

Package Options

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

1 Features

  • Efficiency up to 96%
  • Available in 8-Pin SOIC, PDIP, and WSON Packages
  • Simple and Easy to Design With
  • Requires Only 5 External Components
  • Uses Readily Available Standard Inductors
  • 3.3-V, 5-V, 12-V, and Adjustable Output Versions
  • Adjustable Version Output Voltage Range: 1.21 V to 37 V
  • ±1.5% Maximum Output Voltage Tolerance Over Line and Load Conditions
  • Ensured 500-mA Output Load Current
  • 0.25-Ω DMOS Output Switch
  • Wide Input Voltage Range: 8 V to 40 V
  • 260-kHz Fixed Frequency Internal Oscillator
  • TTL Shutdown Capability, Low Power Standby Mode
  • Soft-Start and Frequency Synchronization
  • Thermal Shutdown and Current-Limit Protection

2 Applications

  • Simple High Efficiency (> 90%) Step-Down (Buck) Regulators
  • Efficient Preregulator for Linear Regulators

3 Description

The LM2671 series of regulators are monolithic integrated circuits built with a LMDMOS process. These regulators provide all the active functions for a step-down (buck) switching regulator, capable of driving a 500-mA load current with excellent line and load regulation. These devices are available in fixed output voltages of 3.3 V, 5 V, 12 V, and an adjustable output version.

Requiring a minimum number of external components, these regulators are simple to use and include patented internal frequency compensation, fixed frequency oscillator, external shutdown, soft start, and frequency synchronization.

The LM2671 series operates at a switching frequency of 260 kHz, thus allowing smaller sized filter components than what is required with lower frequency switching regulators. Because of its very high efficiency (> 90%), the copper traces on the printed-circuit board are the only heat sinking required.

A family of standard inductors for use with the LM2671 are available from several different manufacturers. This feature greatly simplifies the design of switch-mode power supplies using these advanced ICs. Also included in the data sheet are selector guides for diodes and capacitors designed to work in switch-mode power supplies.

Device Information(1)

PART NUMBER PACKAGE BODY SIZE (NOM)
LM2674 SOIC (8) 4.90 mm × 3.91 mm
PDIP (8) 9.81 mm × 6.35 mm
WSON (16) 5.00 mm × 5.00 mm
  1. For all available packages, see the orderable addendum at the end of the data sheet.

Typical Application

LM2671 10004201.png
For fixed output voltage versions