SLVSAT1A June   2011  – July 2022 TPS54325-Q1

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
  6. 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
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Soft Start and Pre-Biased Soft Start
      2. 7.3.2 Power Good
      3. 7.3.3 Output Discharge Control
      4. 7.3.4 Current Protection
      5. 7.3.5 Overvoltage and Undervoltage Protection
      6. 7.3.6 UVLO Protection
      7. 7.3.7 Thermal Shutdown
    4. 7.4 Device Functional Modes
      1. 7.4.1 PWM Operation
      2. 7.4.2 PWM Frequency and Adaptive On-Time Control
  8. 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 Output Inductor Selection
        3. 8.2.2.3 Output Capacitor Selection
        4. 8.2.2.4 Input Capacitor Selection
        5. 8.2.2.5 Bootstrap Capacitor Selection
        6. 8.2.2.6 VREG5 Capacitor Selection
        7. 8.2.2.7 Output Voltage Resistors Selection
      3. 8.2.3 Application Performance Plots
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
    3. 10.3 Thermal Information
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Third-Party Products Disclaimer
      2. 11.1.2 Development Support
        1. 11.1.2.1 Custom Design With WEBENCH® Tools
    2. 11.2 Documentation Support
    3. 11.3 Receiving Notification of Documentation Updates
    4. 11.4 Support Resources
    5. 11.5 Trademarks
    6. 11.6 Electrostatic Discharge Caution
    7. 11.7 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

8.2.2.2 Output Inductor Selection

The inductance value is selected to provide approximately 30% peak-to-peak ripple current at maximum load. Larger ripple current increases output ripple voltage, improves S/N ratio, and contributes to stable operation. Smaller ripple currents result in lower output voltage ripple. When using low-ESR output capacitors, output ripple voltage is usually low, so larger ripple currents are acceptable. The coefficient Kind represents the percentage of ripple current. The value of Kind must not be greater than 0.4. Use 0.3 when using low-ESR output capacitors. Equation 2 can be used to calculate L1. Use 700 kHz for fSW. Make sure the chosen inductor is rated for the peak current of Equation 4 and the RMS current of Equation 5.

Equation 2. L O =   V O U T V I N ( M A X )   ×   V I N ( M A X ) -   V O U T I O U T   ×   f S W   × K i n d
Equation 3. I l p - p =   V O U T V I N M A X   ×   V I N ( M A X )   -   V O U T L O   ×   f S W
Equation 4. I l p e a k =   I O +   I l p   -   p 2
Equation 5. ILo(RMS)= I02+ 112 Ilp- p2