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
7.2.2.2.6 Setting the Output Voltage

Choose resistors R1 and R2 to set the output voltage within a range of 0.8 V to 5.5 V, according to Equation 8. To keep the feedback network robust from noise, and to reduce the self-generated noise of resistors, set R2 equal to or lower than 5 kΩ. Lower values of FB resistors achieve better noise immunity, and lower light load efficiency, as explained in the Design Considerations for a Resistive Feedback Divider in a DC/DC Converter analog design journal.

Equation 8. R 1 = R 2 × V O U T V F B - 1   =   R 2   ×   V O U T 0.8   V   -   1  
VOUT (V) R1 R2
0.9 604 Ω 4.87 kΩ
1.0 1.21 kΩ 4.87 kΩ
1.2 2.43 kΩ 4.87 kΩ
1.8 6.04 kΩ 4.87 kΩ
2.5 10.4 kΩ 4.87 kΩ
3.3 15.2 kΩ 4.87 kΩ
5 25.5 kΩ 4.87 kΩ

A feedforward capacitor (CFF) is not required for proper operation, but can further improve output noise. However, care must be taken in choosing the CFF because the power-good (PG) function can not be valid with a large CFF during start-up, and can cause spurious triggering of the PG pin during a large load transient. Refer to the Pros and Cons Using a Feedforward Capacitor with a Low Dropout Regulator application report for a discussion of the pros and cons of using a feedforward capacitor.