SNVS007I September   1998  – June 2025 LM2674

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1  Absolute Maximum Ratings
    2. 5.2  ESD Ratings
    3. 5.3  Recommended Operating Conditions
    4. 5.4  Thermal Information
    5. 5.5  Electrical Characteristics – 3.3-V Version
    6. 5.6  Electrical Characteristics – 5-V Version
    7. 5.7  Electrical Characteristics – 12-V Version
    8. 5.8  Electrical Characteristics – Adjustable Voltage Version
    9. 5.9  Electrical Characteristics – All Output Voltage Versions
    10. 5.10 Typical Characteristics
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1 Adjustable Output Voltage
    4. 6.4 Device Functional Modes
      1. 6.4.1 Shutdown Mode
      2. 6.4.2 Active Mode
  8. 7 Application and Implementation
    1. 7.1 Application Information
    2. 7.2 Typical Applications
      1. 7.2.1 Fixed Output Voltage Typical Application
        1. 7.2.1.1 Design Requirements
        2. 7.2.1.2 Detailed Design Procedure
          1. 7.2.1.2.1 Custom Design with WEBENCH® Tools
          2. 7.2.1.2.2 Inductor Selection (L1)
          3. 7.2.1.2.3 Output Capacitor Selection (COUT)
          4. 7.2.1.2.4 Catch Diode Selection (D1)
          5. 7.2.1.2.5 Input Capacitor (CIN)
          6. 7.2.1.2.6 Boost Capacitor (CB)
        3. 7.2.1.3 Application Curves
      2. 7.2.2 Adjustable Output Voltage Typical Application
        1. 7.2.2.1 Design Requirements
        2. 7.2.2.2 Detailed Design Procedure
          1. 7.2.2.2.1 Programming Output Voltage
          2. 7.2.2.2.2 Inductor Selection (L1)
          3. 7.2.2.2.3 Output Capacitor Selection (COUT)
          4. 7.2.2.2.4 Catch Diode Selection (D1)
          5. 7.2.2.2.5 Input Capacitor (CIN)
          6. 7.2.2.2.6 Boost Capacitor (CB)
        3. 7.2.2.3 Application Curves
      3. 7.2.3 Typical Application for All Output Voltage Versions
        1. 7.2.3.1 Application Curves
    3. 7.3 Power Supply Recommendations
    4. 7.4 Layout
      1. 7.4.1 Layout Guidelines
        1. 7.4.1.1 WSON Package Devices
      2. 7.4.2 Layout Examples
  9. 8 Device and Documentation Support
    1. 8.1 Device Support
      1. 8.1.1 Development Support
        1. 8.1.1.1 Custom Design with WEBENCH® Tools
    2. 8.2 Documentation Support
      1. 8.2.1 Related Documentation
    3. 8.3 Receiving Notification of Documentation Updates
    4. 8.4 Support Resources
    5. 8.5 Trademarks
    6. 8.6 Electrostatic Discharge Caution
    7. 8.7 Glossary
  10. 9 Revision History
  11. 10Mechanical, Packaging, and Orderable Information

3 Description

The LM2674 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 500mA load current with excellent line and load regulation. These devices are available in fixed output voltages of 3.3V, 5V, 12V, and an adjustable output version.

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

The LM2674 series operates at a switching frequency of 260kHz, thus allowing smaller sized filter components than what is required with lower frequency switching regulators. Because of 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 LM2674 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.

Package Information
PART NUMBER PACKAGE(1) PACKAGE SIZE(2)
LM2674 D (SOIC, 8) 4.9mm × 6mm
P (PDIP, 8) 9.81mm × 9.43mm
NHN (WSON, 16) 5mm × 5mm
(1) For more information, see Section 10.
(2) The package size (length × width) is a nominal value and includes pins, where applicable.
LM2674 Typical Application Typical Application

Other features include a specified ±1.5% tolerance on output voltage within specified input voltages and output load conditions, and ±10% on the oscillator frequency. External shutdown is included, featuring typically 50μA standby current. The output switch includes current limiting, as well as thermal shutdown for full protection under fault conditions.