SLVSEF9I March   2018  – March 2024 TPS62824 , TPS62824A , TPS62825 , TPS62825A , TPS62826 , TPS62826A , TPS62827 , TPS62827A

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Options
  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 Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Pulse Width Modulation (PWM) Operation
      2. 7.3.2 Power Save Mode (PSM) Operation
      3. 7.3.3 Minimum Duty Cycle and 100% Mode Operation
      4. 7.3.4 Soft Start
      5. 7.3.5 Switch Current Limit and HICCUP Short-Circuit Protection
      6. 7.3.6 Undervoltage Lockout
      7. 7.3.7 Thermal Shutdown
    4. 7.4 Device Functional Modes
      1. 7.4.1 Enable, Disable, and Output Discharge
      2. 7.4.2 Power Good
  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 Custom Design With WEBENCH® Tools
        2. 8.2.2.2 Setting The Output Voltage
        3. 8.2.2.3 Output Filter Design
        4. 8.2.2.4 Inductor Selection
        5. 8.2.2.5 Capacitor Selection
      3. 8.2.3 Application Curves
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Example
        1. 8.4.2.1 Thermal Considerations
  10. 9 Device and Documentation Support
    1. 9.1 Device Support
      1. 9.1.1 Third-Party Products Disclaimer
      2. 9.1.2 Development Support
        1. 9.1.2.1 Custom Design With WEBENCH® Tools
    2. 9.2 Documentation Support
      1. 9.2.1 Related Documentation
    3. 9.3 Support Resources
    4. 9.4 Trademarks
    5. 9.5 Electrostatic Discharge Caution
    6. 9.6 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information

8.2.2.2 Setting The Output Voltage

The output voltage is set by an external resistor divider according to Equation 4:

Equation 4. R1=R2×VOUTVFB-1=R2×VOUT0.6 V-1

R2 must not be higher than 100kΩ to achieve high efficiency at light load while providing acceptable noise sensitivity. Equation 5 shows how to compute the value of the feedforward capacitor for a given R2 value. For the recommended 100k value for R2, a 120pF feedforward capacitor is used.

Equation 5. C3=12μR2

For the fixed output voltage versions, connect the FB pin to the output. R1, R2, and C3 are not needed. The fixed output voltage devices have an internal feedforward capacitor.