SNVS405G December   2005  – April 2015 LM3674

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
  6. 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 Dissipation Ratings
    6. 6.6 Electrical Characteristics
    7. 6.7 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Circuit Operation
      2. 7.3.2 PWM Operation
        1. 7.3.2.1 Internal Synchronous Rectification
        2. 7.3.2.2 Current Limiting
    4. 7.4 Device Functional Modes
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Soft-Start
      2. 8.1.2 Low-Dropout (LDO) Operation
    2. 8.2 Typical Applications
      1. 8.2.1 Typical Application for Fixed Voltage Configuration
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
          1. 8.2.1.2.1 Inductor Selection
          2. 8.2.1.2.2 Input Capacitor Selection
          3. 8.2.1.2.3 Output Capacitor Selection
        3. 8.2.1.3 Application Curves
      2. 8.2.2 Typical Application Circuit for Adjustable Voltage Option
        1. 8.2.2.1 Design Requirements
        2. 8.2.2.2 Detailed Design Procedure
          1. 8.2.2.2.1 Output Voltage Selection for Adjustable (LM3674-ADJ)
        3. 8.2.2.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Third-Party Products Disclaimer
    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

  • Input Voltage Range From 2.7 V to 5.5 V
  • 600-mA Maximum Load Current
  • Available in Fixed and Adjustable Output Voltages Ranging From 1 V to 3.3 V
  • Operates From a Single Li-Ion Cell Battery
  • Internal Synchronous Rectification for High Efficiency
  • Internal Soft-Start
  • 0.01-µA Typical Shutdown Current
  • 2-MHz PWM Fixed Switching Frequency (typical)
  • Current Overload Protection and Thermal Shutdown Protection

2 Applications

  • Mobile Phones
  • PDAs
  • MP3 Players
  • Portable Instruments
  • W-LAN
  • Digital Still Cameras
  • Portable Hard Disk Drives

3 Description

The LM3674 step-down DC-DC converter is optimized for powering low-voltage circuits from a single Li-Ion cell battery and input voltage rails from 2.7 V to 5.5 V. It provides up to 600-mA load current over the entire input voltage range. There are several fixed output voltages and adjustable output voltage versions.

The device offers superior features and performance for mobile phones and similar portable systems. During the Pulse Width Modulation (PWM) mode, the device operates at a fixed-frequency of 2 MHz (typical). Internal synchronous rectification provides high efficiency during the PWM mode operation. In shutdown mode, the device turns off and reduces battery consumption to 0.01 µA (typical).

The LM3674 is available in a 5-pin SOT-23 package. A high switching frequency of 2 MHz (typical) allows use of only three tiny external surface-mount components, an inductor and two ceramic capacitors.

Device Information(1)

PART NUMBER PACKAGE BODY SIZE (NOM)
LM3674 SOT-23 (5) 2.90 mm × 1.60 mm
  1. For all available packages, see the orderable addendum at the end of the data sheet.

Typical Application Circuit

LM3674 20167201.gif

Typical Application Circuit for Adjustable Voltage Option

LM3674 20167230.gif