SNAS344F December   2005  – June 2025 LM4674

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Key Specifications
  5. 4 DESCRIPTION
  6. 5 Pin Configuration and Functions
  7. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 Operating Ratings
    3. 6.3 Electrical Characteristics VDD = 3.6V
    4. 6.4 Typical Performance Characteristics
  8. 7 Block Diagrams
  9. 8 Application Information
    1. 8.1  General Amplifier Function
    2. 8.2  Differential Amplifier Explanation
    3. 8.3  Power Dissipation and Efficency
    4. 8.4  Shutdown Function
    5. 8.5  Single-Ended Audio Amplifier Configuration
    6. 8.6  Audio Amplifier Power Supply Bypassing/Filtering
    7. 8.7  Audio Amplifier Input Capacitor Selection
    8. 8.8  Audio Amplifier Gain Setting
    9. 8.9  Output Filter Considerations
    10. 8.10 Layout Guidelines
    11. 8.11 LM4674TL Demo Board Schematic
    12. 8.12 LM4674TL Demonstration Board Layout
    13. 8.13 LM4674SQ Demo Board Schematic
    14. 8.14 LM4674SQ Demonstration Board Layout
    15. 8.15 Trademarks
  10. 9 Typical Application
  11. 10Development Support
    1. 10.1 Third-Party Products Disclaimer
    2. 10.2 Device Nomenclature Boilerplate
  12. 11Receiving Notification of Documentation Updates
  13. 12Electrostatic Discharge Caution
  14. 13Glossary
  15. 14Revision History
  16. 15Mechanical, Packaging, and Orderable Information

4 DESCRIPTION

The LM4674 is a single supply, high efficiency, 2.5W/channel, filterless switching audio amplifier. A low noise PWM architecture eliminates the output filter, reducing external component count, board area consumption, system cost, and simplifying design.

The LM4674 is designed to meet the demands of mobile phones and other portable communication devices. Operating from a single 5V supply, the device is capable of delivering 2.5W/channel of continuous output power to a 4Ω load with less than 10% THD+N. Flexible power supply requirements allow operation from 2.4V to 5.5V.

The LM4674 features high efficiency compared to conventional Class AB amplifiers. When driving an 8Ω speaker from a 3.6V supply, the device features 85% efficiency at PO = 500mW. Four gain options are pin selectable through the G0 and G1 pins.

Output short circuit protection prevents the device from being damaged during fault conditions. Click and pop suppression eliminates audible transients on power-up/down and during shutdown. Independent left/right shutdown control maximizes power savings in mixed mono/stereo applications.