SNVS434M July   2006  – November 2016 LM3673

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Voltage Options
  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 Ratings
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 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 Circuit Operation
      2. 8.3.2 PWM Operation
      3. 8.3.3 Internal Synchronous Rectification
      4. 8.3.4 Current Limiting
      5. 8.3.5 Soft Start
      6. 8.3.6 Low Drop Out Operation (LDO)
    4. 8.4 Device Functional Modes
      1. 8.4.1 PFM Operation
      2. 8.4.2 Shutdown Mode
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Applications
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Output Voltage Selection for LM3673-ADJ
        2. 9.2.2.2 Inductor Selection
          1. 9.2.2.2.1 Method 1
          2. 9.2.2.2.2 Method 2
        3. 9.2.2.3 Input Capacitor Selection
        4. 9.2.2.4 Output Capacitor Selection
      3. 9.2.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
    3. 11.3 DSBGA Package Assembly and Use
  12. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 Third-Party Products Disclaimer
    2. 12.2 Documentation Support
      1. 12.2.1 Related Documentation
    3. 12.3 Receiving Notification of Documentation Updates
    4. 12.4 Community Resources
    5. 12.5 Trademarks
    6. 12.6 Electrostatic Discharge Caution
    7. 12.7 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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

1 Features

  • 16-µA Typical Quiescent Current
  • 350-mA Maximum Load Capability
  • 2-MHz PWM Fixed Switching Frequency (Typical)
  • Automatic PFM/PWM Mode Switching
  • Available in Fixed and Adjustable Output Voltages
  • Internal Synchronous Rectification for High Efficiency
  • Internal Soft Start
  • 0.01-µA Typical Shutdown Current
  • Operates From a Single Li-Ion Cell Battery
  • Current Overload and Thermal Shutdown Protection
  • Only Three Tiny Surface-Mount External Components Required (One Inductor, Two Ceramic Capacitors)

2 Applications

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

3 Description

The LM3673 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 350-mA load current over the entire input voltage range. There are several different fixed voltage output options available, as well as an adjustable output voltage version ranging from 1.1 V to 3.3 V.

The device offers superior features and performance for mobile phones and similar portable systems. The LM3673 uses intelligent automatic switching between pulse width modulation (PWM) and pulse frequency modulation (PFM) for better efficiency. During PWM mode, the device operates at a fixed-frequency of
2 MHz (typical). Hysteretic PFM mode extends the battery life by reducing the quiescent current to 16 µA (typical) during light load and standby operation. Internal synchronous rectification provides high efficiency during PWM mode operation. In shutdown mode, the device turns off and reduces battery consumption to 0.01 µA (typical).

The LM3673 is available in a tiny 5-pin DSBGA package. A high switching frequency of 2 MHz (typical) allows the use of three tiny surface-mount components: an inductor and two ceramic capacitors.

Device Information(1)

PART NUMBER PACKAGE BODY SIZE (MAX)
LM3673 DSBGA (5) 1.413 mm × 1.083 mm
  1. For all available packages, see the orderable addendum at the end of the data sheet.


Typical Application Circuit

LM3673 20183001.gif

Typical Application Circuit for ADJ Version

LM3673 20183331.gif