SNVS506J May   2008  – December 2015 LM3691

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 Conditions
    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
        1. 8.3.2.1 Internal Synchronous Rectification
        2. 8.3.2.2 Current Limiting
      3. 8.3.3 ECO Operation
      4. 8.3.4 Soft-Start
      5. 8.3.5 Thermal Shutdown Protection
      6. 8.3.6 Overtemperature Maximum Load
    4. 8.4 Device Functional Modes
      1. 8.4.1 Forced PWM Mode
      2. 8.4.2 Shutdown Mode
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Inductor Selection
        2. 9.2.2.2 Input Capacitor Selection
        3. 9.2.2.3 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 Community Resources
    4. 12.4 Trademarks
    5. 12.5 Electrostatic Discharge Caution
    6. 12.6 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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

1 Features

  • Input Voltage: 2.3 V to 5.5 V
  • Output Voltage: 0.75 V to 3.3 V
  • ±1% DC Output Voltage Precision
  • 4-MHz Switching Frequency
  • 64-μA (typical) Quiescent Current in ECO Mode
  • 1-A Maximum Load Capability
  • Automatic ECO/PWM Mode Switching
  • MODE Pin to Select ECO/Forced PWM Mode
  • Current Overload and Thermal Shutdown Protections
  • Only Three Tiny Surface-Mount External Components Required (Solution Size Less Than 15 mm2)

2 Applications

  • Mobile Phones
  • Hand-Held Radios
  • MP3 Players
  • Portable Hard Disk Drives

3 Description

The LM3691 step-down DC-DC converter is optimized for powering ultra-low-voltage circuits from a single Li-Ion cell or 3 cell NiMH/NiCd batteries. It provides up to 1-A load current over an input voltage range from 2.3 V to 5.5 V. There are several different fixed voltage output options available.

The LM3691 has a mode-control pin that allows the user to select Forced PWM mode or ECO mode that changes modes between gated PWM mode and PWM automatically, depending on the load. In ECO mode, the device offers superior efficiency and very low IQ under light load conditions. ECO mode extends the battery life through reduction of the quiescent current during light load conditions and system standby.

The LM3691 is available in a 6-pin DSBGA package. Only three external surface-mount components, a
1-μH inductor, a 4.7-μF input capacitor, and a 4.7-μF output capacitor, are required.

Device Information(1)

PART NUMBER PACKAGE BODY SIZE (MAX)
LM3691 DSBGA (6) 1.59 mm × 1.295 mm
  1. For all available packages, see the orderable addendum at the end of the data sheet.

Typical Application Circuit

LM3691 typapp_snvs506.gif

Efficiency vs. Output Current
(VOUT = 1.8 V, ECO Mode)

LM3691 30013466.gif