SLVSD88M July   2016  – August 2026 TPS61099

PRODMIX  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison Table
  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 Boost Controller Operation
      2. 7.3.2 Undervoltage Lockout
      3. 7.3.3 Enable and Disable
      4. 7.3.4 Soft Start
      5. 7.3.5 Current Limit Operation
      6. 7.3.6 Output Short-to-Ground Protection
      7. 7.3.7 Overvoltage Protection
      8. 7.3.8 Down Mode Regulation and Pass-Through Operation
      9. 7.3.9 Thermal Shutdown
    4. 7.4 Device Functional Modes
      1. 7.4.1 Burst Mode Operation under Light Load Condition
      2. 7.4.2 Down Mode Regulation and Pass-Through Mode Operation
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application - 5V Output Boost Converter
      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 Programming the Output Voltage
        3. 8.2.2.3 Maximum Output Current
        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
  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 Receiving Notification of Documentation Updates
    4. 9.4 Support Resources
    5. 9.5 Trademarks
    6. 9.6 Electrostatic Discharge Caution
    7. 9.7 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information

8.2.2.5 Capacitor Selection

For best output and input voltage filtering, TI recommends low ESR X5R or X7R ceramic capacitors.

The input capacitor minimizes input voltage ripple, suppresses input voltage spikes and provides a stable system rail for the device. An input capacitor value of 10μF is normally recommended to improve transient behavior of the regulator and EMI behavior of the total power supply circuit. A ceramic capacitor placed as close as possible to the VIN and GND pins of the IC is recommended.

For the output capacitor of VOUT pin, TI recommends small ceramic capacitors placed as close as possible to the VOUT and GND pins of the IC. If, for any reason, the application requires the use of large capacitors which cannot be placed close to the IC, TI recommends the use of a small ceramic capacitor with a capacitance value of 1μF in parallel to the large one. This small capacitor must be placed as close as possible to the VOUT and GND pins of the IC.

From the power stage point of view, the output capacitor sets the corner frequency of the converter while the inductor creates a Right-Half-Plane-Zero. Consequently, with a larger inductor, a larger output capacitor must be used. The TPS61099x is optimized to work with the inductor from 1µH to 2.2µH, so the minimal output capacitor value is 20μF (nominal value). Increasing the output capacitor makes the output ripple smaller in PWM mode.

When selecting capacitors, ceramic capacitor derating effect under bias must be considered. Select the right nominal capacitance by checking the capacitor DC bias characteristics. In this example, GRM188R60J106ME84D, which is a 10µF ceramic capacitor with high effective capacitance value at DC biased condition, is selected for VOUT rail. The performance of TPS61099x is shown in Application Curves section.