SBVS454 May   2024 TLV771

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 Switching Characteristics
    7. 5.7 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 Dropout Voltage
      2. 6.3.2 Active Discharge
      3. 6.3.3 Foldback Current Limit
      4. 6.3.4 Thermal Shutdown
    4. 6.4 Device Functional Modes
      1. 6.4.1 Normal Operation
      2. 6.4.2 Dropout Operation
      3. 6.4.3 Disabled
  8. 7 Application and Implementation
    1. 7.1 Application Information
      1. 7.1.1 Recommended Capacitor Types
      2. 7.1.2 Input and Output Capacitor Requirements
    2. 7.2 Typical Application
      1. 7.2.1 Application
      2. 7.2.2 Design Requirements
      3. 7.2.3 Detailed Design Procedure
      4. 7.2.4 Application Curves
    3. 7.3 Power Supply Recommendations
    4. 7.4 Layout
      1. 7.4.1 Layout Guidelines
      2. 7.4.2 Layout Examples
  9. 8 Device and Documentation Support
    1. 8.1 Documentation Support
      1. 8.1.1 Related Documentation
      2. 8.1.2 Device Nomenclature
    2. 8.2 Receiving Notification of Documentation Updates
    3. 8.3 Support Resources
    4. 8.4 Trademarks
    5. 8.5 Electrostatic Discharge Caution
    6. 8.6 Glossary
  10. 9 Revision History
  11. 10Mechanical, Packaging, and Orderable Information

6.4.2 Dropout Operation

If the input voltage is lower than the nominal output voltage plus the specified dropout voltage, the device operates in dropout mode. In this mode, the output voltage tracks the input voltage. In this mode, the transient performance of the device becomes significantly degraded. During this mode, the pass transistor is driven fully on. Line or load transients in dropout potentially result in large output voltage deviations.

When the device is in a steady dropout state, the pass transistor is driven fully on. This state is defined as when the device is in dropout, directly after being in a normal regulation state, but not during start-up. Dropout occurs when VIN < VOUT(NOM) + VDO. When the regulator exits dropout, the input voltage returns to a value ≥VOUT(NOM) + VDO. During this time, the output voltage potentially overshoots for a short period of time. VOUT(NOM) is the nominal output voltage and VDO is the dropout voltage. During dropout exit, the device pulls the pass transistor back from being driven fully on.