SNVS037H September   1999  – March 2024 LM1084

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
    6. 5.6 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 Ripple Rejection
      2. 6.3.2 Load Regulation
      3. 6.3.3 Overload Recovery
    4. 6.4 Device Functional Modes
      1. 6.4.1 Output Voltage
      2. 6.4.2 Stability Consideration
      3. 6.4.3 Protection Diodes
  8. 7 Application and Implementation
    1. 7.1 Application Information
    2. 7.2 Typical Applications
      1. 7.2.1  1.2-V to 15-V Adjustable Regulator
        1. 7.2.1.1 Design Requirements
        2. 7.2.1.2 Detailed Design Procedure
        3. 7.2.1.3 Application Curve
      2. 7.2.2  Adjustable at 5 V
      3. 7.2.3  5-V Regulator With Shutdown
      4. 7.2.4  Battery Charger
      5. 7.2.5  Adjustable Fixed Regulator
      6. 7.2.6  Regulator with Reference
      7. 7.2.7  High Current Lamp Driver Protection
      8. 7.2.8  Battery Backup Regulated Supply
      9. 7.2.9  Ripple Rejection Enhancement
      10. 7.2.10 Automatic Light Control
      11. 7.2.11 Generating Negative Supply Voltage
      12. 7.2.12 Remote Sensing
    3. 7.3 Power Supply Recommendations
    4. 7.4 Layout
      1. 7.4.1 Layout Guidelines
        1. 7.4.1.1 Thermal Considerations
      2. 7.4.2 Layout Example
  9. 8 Device and Documentation Support
    1. 8.1 Receiving Notification of Documentation Updates
    2. 8.2 Support Resources
    3. 8.3 Trademarks
    4. 8.4 Electrostatic Discharge Caution
    5. 8.5 Glossary
  10. 9 Revision History
  11. 10Mechanical, Packaging, and Orderable Information

Package Options

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

7.2.8 Battery Backup Regulated Supply

A regulated battery backup supply can be generated by using two fixed output voltage versions of the part as shown in Figure 7-8. The top regulator supplies the Line voltage during normal operation, however when the input is not available, the second regulator derives power from the battery backup and regulates it to 5 V based on the LM1084-5.0. The diodes prevent the rails from back feeding into the supply and batteries.

GUID-01F90E27-E703-4C67-BE77-4D9857116BB9-low.pngFigure 7-8 Battery Backup Regulated Supply