SLVSG94C November   2023  – June 2024 TPS62914 , TPS62916 , TPS62918

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 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  Smart Config (S-CONF)
      2. 6.3.2  Device Enable (EN/SYNC)
      3. 6.3.3  Device Synchronization (EN/SYNC)
      4. 6.3.4  Spread Spectrum Modulation
      5. 6.3.5  Output Discharge
      6. 6.3.6  Undervoltage Lockout (UVLO)
      7. 6.3.7  Power-Good Output
      8. 6.3.8  Noise Reduction and Soft-Start Capacitor (NR/SS)
      9. 6.3.9  Current Limit and Short-Circuit Protection
      10. 6.3.10 Thermal Shutdown
    4. 6.4 Device Functional Modes
      1. 6.4.1 Fixed Frequency Pulse Width Modulation
      2. 6.4.2 Low Duty Cycle Operation
      3. 6.4.3 High Duty Cycle Operation (100% Duty Cycle)
      4. 6.4.4 Second Stage L-C Filter Compensation (Optional)
  8. 7 Application and Implementation
    1. 7.1 Application Information
    2. 7.2 Typical Applications
      1. 7.2.1 Design Requirements
      2. 7.2.2 Detailed Design Procedure
        1. 7.2.2.1 Custom Design With WEBENCH® Tools
        2. 7.2.2.2 External Component Selection
          1. 7.2.2.2.1 Switching Frequency Selection
          2. 7.2.2.2.2 Inductor Selection for the First L-C Filter
          3. 7.2.2.2.3 Output Capacitor Selection
          4. 7.2.2.2.4 Ferrite Bead Selection for Second L-C Filter
          5. 7.2.2.2.5 Input Capacitor Selection
          6. 7.2.2.2.6 Setting the Output Voltage
          7. 7.2.2.2.7 Bootstrap Capacitor Selection
          8. 7.2.2.2.8 NR/SS Capacitor Selection
      3. 7.2.3 Application Curves
    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
7.2.2.2.2 Inductor Selection for the First L-C Filter

The inductor must be rated for the appropriate saturation current. Equation 5 and Equation 6 calculate the maximum inductor current under static load conditions. The formula takes the converter efficiency into account. The calculation must be done for the maximum input voltage where the peak switch current is highest.

Equation 5. ∆ I L =   V O U T η   × 1   -   V O U T V I N ×   η f S W   ×   L  
Equation 6. I P E A K = I O U T + ∆ I L 2

where:

  • ƒSW is the switching frequency (1 MHz, 1.4 MHz, or 2.2 MHz)
  • L = inductance
  • η = estimated efficiency (use the value from the efficiency curves or 0.9 as an conservative assumption)
Note: The calculation must be done for the maximum input voltage of the application.

Calculating the maximum inductor current using the actual operating conditions gives the minimum saturation current. TI recommends a margin of 20% be added to cover for load transients during operation.

See Table 7-4 for typical inductors.

Table 7-4 Inductor Selection
INDUCTOR VALUE MANUFACTURER PART NUMBER SIZE (L × W × H IN mm) ISAT/DCR (30% DROP)
1 µH Coilcraft XGL4020-102 4 × 4 × 2.1 8.8 A / 8.2 mΩ
1 µH Coilcraft XGL4030-102 4 × 4 × 3.1 10.3 A / 6.5 mΩ
1 µH Wurth Elektronik 74438356010 4.1 × 4.1 × 2.1 9 A / 12 mΩ
1 µH Wurth Elektronik 74438357010 4.1 × 4.1 × 3.1 9.6 / 11.6 mΩ
1 µH Coilcraft XGL5020-102 5 × 5 × 2.1 11.4 A / 7.5 mΩ
1 µH Coilcraft XGL5030-102 5 × 5 × 3.1 14 A / 4.8 mΩ