SNVSA85D October   2015  – October 2025 LM27761

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 Undervoltage Lockout
      2. 6.3.2 Input Current Limit
      3. 6.3.3 PFM Operation
      4. 6.3.4 Output Discharge
      5. 6.3.5 Thermal Shutdown
    4. 6.4 Device Functional Modes
      1. 6.4.1 Shutdown Mode
      2. 6.4.2 Enable Mode
  8. 7 Application and Implementation
    1. 7.1 Application Information
    2. 7.2 Typical Application - Regulated Voltage Inverter
      1. 7.2.1 Design Requirements
      2. 7.2.2 Detailed Design Procedure
        1. 7.2.2.1 Charge-Pump Voltage Inverter
        2. 7.2.2.2 Negative Low-Dropout Linear Regulator
        3. 7.2.2.3 Power Dissipation
        4. 7.2.2.4 Output Voltage Setting
        5. 7.2.2.5 External Capacitor Selection
          1. 7.2.2.5.1 Charge-Pump Output Capacitor
          2. 7.2.2.5.2 Input Capacitor
          3. 7.2.2.5.3 Flying Capacitor
          4. 7.2.2.5.4 LDO Output Capacitor
      3. 7.2.3 Application Curves
    3. 7.3 Power Supply Recommendations
    4. 7.4 Layout
      1. 7.4.1 Layout Guidelines
      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
7.2.2.5.3 Flying Capacitor

The flying capacitor (C1) transfers charge from the input to the output. Flying capacitance can impact both output current capability and ripple magnitudes. If flying capacitance is too small, the LM27761 can not be able to regulate the output voltage when load currents are high. If the flying capacitance is too large, the flying capacitor can overwhelm the input and charge pump output capacitors, resulting in increased input and output ripple.

In typical high-current applications, TI recommends 0.47-µF or 1-µF 10-V low-ESR ceramic capacitors for the flying capacitors. Polarized capacitors (tantalum, aluminum, electrolytic, and so forth.) must not be used for the flying capacitor, as polarized capacitors can become reverse-biased during LM27761 operation.