SLVS632L January   2006  – April 2026 TPS5430 , TPS5431

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 (DDA Package)
    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  Oscillator Frequency
      2. 6.3.2  Voltage Reference
      3. 6.3.3  Enable (ENA) and Internal Slow Start
      4. 6.3.4  Undervoltage Lockout (UVLO)
      5. 6.3.5  Boost Capacitor (BOOT)
      6. 6.3.6  Output Feedback (VSENSE) and Internal Compensation
      7. 6.3.7  Voltage Feed-Forward
      8. 6.3.8  Pulse-Width-Modulation (PWM) Control
      9. 6.3.9  Overcurrent Limiting
      10. 6.3.10 Overvoltage Protection
      11. 6.3.11 Thermal Shutdown
    4. 6.4 Device Functional Modes
      1. 6.4.1 Operation near Minimum Input Voltage
      2. 6.4.2 Operation With ENA control
  8. 7 Application and Implementation
    1. 7.1 Application Information
    2. 7.2 Typical Applications
      1. 7.2.1 12V Input to 5.0V Output
        1. 7.2.1.1 Design Requirements
        2. 7.2.1.2 Detailed Design Procedure
          1. 7.2.1.2.1 Custom Design With WEBENCH® Tools
          2. 7.2.1.2.2 Switching Frequency
          3. 7.2.1.2.3 Input Capacitors
          4. 7.2.1.2.4 Output Filter Components
            1. 7.2.1.2.4.1 Inductor Selection
            2. 7.2.1.2.4.2 Capacitor Selection
          5. 7.2.1.2.5 Output Voltage Set-Point
          6. 7.2.1.2.6 BOOT Capacitor
          7. 7.2.1.2.7 Catch Diode
          8. 7.2.1.2.8 Advanced Information
            1. 7.2.1.2.8.1 Output Voltage Limitations
            2. 7.2.1.2.8.2 Internal Compensation Network
            3. 7.2.1.2.8.3 Thermal Calculations
        3. 7.2.1.3 Application Curves
      2. 7.2.2 Wide Input Voltage Ranges With TPS5430
        1. 7.2.2.1 Design Requirements
        2. 7.2.2.2 Detailed Design Procedure
        3. 7.2.2.3 Wide Input Voltage Ranges with TPS5431
          1. 7.2.2.3.1 Design Requirements
          2. 7.2.2.3.2 Detailed Design Procedure
      3. 7.2.3 Circuit Using Ceramic Output Filter Capacitors
        1. 7.2.3.1 Design Requirements
        2. 7.2.3.2 Detailed Design Procedure
          1. 7.2.3.2.1 Output Filter Component Selection
          2. 7.2.3.2.2 External Compensation Network
    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 Device Support
      1. 8.1.1 Third-Party Products Disclaimer
      2. 8.1.2 Development Support
        1. 8.1.2.1 Custom Design With WEBENCH® Tools
    2. 8.2 Documentation Support
      1. 8.2.1 Related Documentation
    3. 8.3 Receiving Notification of Documentation Updates
    4. 8.4 Support Resources
    5. 8.5 Trademarks
    6. 8.6 Electrostatic Discharge Caution
    7. 8.7 Glossary
  10. 9 Revision History
  11. 10Mechanical, Packaging, and Orderable Information
7.2.3.2.1 Output Filter Component Selection

Using Equation 11, the minimum inductor value is 12μH. A value of 15μH is chosen for this design.

When using ceramic output filer capacitors, the recommended LC resonant frequency must be no more than 7 kHz. Because the output inductor is already selected at 15μH, this limits the minimum output capacitor value to:

Equation 16. TPS5430 TPS5431

The minimum capacitor value is calculated to be 34 μF. For this circuit a larger value of capacitor yields better transient response. A single 100μF output capacitor is used for C3. MAke sure to note that the actual capacitance of ceramic capacitors decreases with applied voltage. In this example, the output voltage is set to 3.3V, minimizing this effect.