SNVS039J June   2000  – April 2015 LM1086

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Typical Application
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin 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 Electrical Characteristics
    6. 6.6 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 Ripple Rejection
      2. 7.3.2 Load Regulation
      3. 7.3.3 Overload Recovery
    4. 7.4 Device Functional Modes
      1. 7.4.1 Output Voltage
      2. 7.4.2 Stability Consideration
      3. 7.4.3 Protection Diodes
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1  1.2-V to 15-V Adjustable Regulator
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
        3. 8.2.1.3 Application Curve
      2. 8.2.2  Adjustable at 5 V
      3. 8.2.3  5-V Regulator with Shutdown
      4. 8.2.4  Battery Charger
      5. 8.2.5  Adjustable Fixed Regulator
      6. 8.2.6  Regulator With Reference
      7. 8.2.7  High Current Lamp Driver Protection
      8. 8.2.8  Battery Backup Regulated Supply
      9. 8.2.9  Ripple Rejection Enhancement
      10. 8.2.10 Automatic Light Control
      11. 8.2.11 Remote Sensing
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
    3. 10.3 Thermal Considerations
  11. 11Device and Documentation Support
    1. 11.1 Development Support
    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

7.4.1 Output Voltage

The LM1086 adjustable version develops a 1.25-V reference voltage, (VREF), between the output and the adjust terminal. As shown in Figure 16, this voltage is applied across resistor R1 to generate a constant current I1. This constant current then flows through R2. The resulting voltage drop across R2 adds to the reference voltage to sets the desired output voltage.

The current IADJ from the adjustment terminal introduces an output error . But since it is small (120uA max), it becomes negligible when R1 is in the 100 Ω range.

For fixed voltage devices, R1 and R2 are integrated inside the devices.

LM1086 10094817.pngFigure 16. Basic Adjustable Regulator