SNVSA56B May   2015  – February 2017 LM2776

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Typical Application
      2.      Output Impedance vs Input Voltage IOUT = 100 mA
  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 Switching 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 Input Current Limit
      2. 7.3.2 PFM Operation
      3. 7.3.3 Output Discharge
      4. 7.3.4 Thermal Shutdown
      5. 7.3.5 Undervoltage Lockout
    4. 7.4 Device Functional Modes
      1. 7.4.1 Shutdown Mode
      2. 7.4.2 Enable Mode
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application - Voltage Inverter
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Requirements
        1. 8.2.2.1 Efficiency
        2. 8.2.2.2 Power Dissipation
        3. 8.2.2.3 Capacitor Selection
        4. 8.2.2.4 Output Capacitor and Output Voltage Ripple
        5. 8.2.2.5 Input Capacitor
        6. 8.2.2.6 Flying Capacitor
      3. 8.2.3 Application Curve
  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 Receiving Notification of Documentation Updates
    3. 11.3 Community Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

7.3.2 PFM Operation

To minimize quiescent current during light load operation, the LM2776 allows PFM or pulse-skipping operation. By allowing the charge pump to switch less when the output current is less than 40 mA, the quiescent current drawn from the power source is minimized. The frequency of pulsed operation is not limited and can drop into the sub-1-kHz range when unloaded. As the load increases, the frequency of pulsing increases until it transitions to constant frequency. The fundamental switching frequency of the LM2776 is 2 MHz.