SBVS097G march   2008  – june 2023 TPS799-Q1

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Revision History
  6. 5 Pin Configuration and Functions
  7. 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
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagrams
    3. 7.3 Feature Description
      1. 7.3.1 Internal Current Limit
      2. 7.3.2 Shutdown
      3. 7.3.3 Dropout Voltage
      4. 7.3.4 Start-Up
      5. 7.3.5 Undervoltage Lockout (UVLO)
    4. 7.4 Device Functional Modes
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Input and Output Capacitor Requirements
        2. 8.2.2.2 Feedback Capacitor Requirements (TPS79901-Q1 Only)
        3. 8.2.2.3 Output Noise
        4. 8.2.2.4 Transient Response
        5. 8.2.2.5 Minimum Load
      3. 8.2.3 Application Curve
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
        1. 8.4.1.1 Board Layout Recommendations to Improve PSRR and Noise Performance
        2. 8.4.1.2 Thermal Consideration
        3. 8.4.1.3 Power Dissipation
        4. 8.4.1.4 Package Mounting
      2. 8.4.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Documentation Support
      1. 9.1.1 Related Documentation
    2. 9.2 Receiving Notification of Documentation Updates
    3. 9.3 Support Resources
    4. 9.4 Trademarks
    5. 9.5 Electrostatic Discharge Caution
    6. 9.6 Glossary
  11. 10Mechanical, Packaging, and Orderable Information

Package Options

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

7.3.3 Dropout Voltage

The TPS799-Q1 uses a PMOS pass transistor to achieve low dropout. When (VIN – VOUT) is less than the dropout voltage (VDO), the PMOS pass transistor is in the linear region of operation and the input-to-output resistance is the RDS, ON of the PMOS pass transistor. Because the PMOS transistor behaves like a resistor in dropout, VDO scales approximately with output current.

As with any linear regulator, PSRR and transient response are degraded as (VIN – VOUT) approaches dropout. This effect is illustrated in Figure 6-7 through Figure 6-9 in the Typical Characteristics section.