SLVS790E November   2007  – April 2019 TPS61165

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Typical Application
  4. 4 Revision History
  5. 5 Device Options
  6. 6 Pin Configuration and Functions
    1.     Pin Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 Recommended Operating Conditions
    3. 7.3 Thermal Information
    4. 7.4 Electrical Characteristics
    5. 7.5 Timing Requirements
    6. 7.6 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Soft Start-Up
      2. 8.3.2 Open LED Protection
      3. 8.3.3 Undervoltage Lockout
      4. 8.3.4 Thermal Shutdown
    4. 8.4 Device Functional Modes
      1. 8.4.1 Shutdown
  9. 9 Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 Maximum Output Current
      2. 9.1.2 Inductor Selection
      3. 9.1.3 Schottky Diode Selection
      4. 9.1.4 Compensation Capacitor Selection
      5. 9.1.5 Input and Output Capacitor Selection
    2. 9.2 Typical Applications
      1. 9.2.1 TPS61165 Typical Application
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
          1. 9.2.1.2.1 LED Brightness Dimming Mode Selection
          2. 9.2.1.2.2 PWM Brightness Dimming
          3. 9.2.1.2.3 Digital One-Wire Brightness Dimming
          4. 9.2.1.2.4 EasyScale: One-Wire Digital Dimming
          5. 9.2.1.2.5 Current Program
        3. 9.2.1.3 Application Curves
      2. 9.2.2 Additional Application Circuits
    3. 9.3 Do's and Don'ts
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
    3. 11.3 Thermal Considerations
  12. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 Third-Party Products Disclaimer
    2. 12.2 Documentation Support
      1. 12.2.1 Related Documentation
    3. 12.3 Community Resources
    4. 12.4 Trademarks
    5. 12.5 Electrostatic Discharge Caution
    6. 12.6 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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

9.1.5 Input and Output Capacitor Selection

The output capacitor is mainly selected to meet the requirements for the output ripple and loop stability. This ripple voltage is related to the capacitor’s capacitance and its equivalent series resistance (ESR). Assuming a capacitor with zero ESR, the minimum capacitance needed for a given ripple can be calculated as shown in Equation 4.

Equation 4. TPS61165 q6_cout_lvs790.gif

where

  • Vripple = peak-to-peak output ripple

The additional output ripple component caused by ESR is calculated as shown in Equation 4.

Equation 5. Vripple_ESR= Iout × RESR

Due to its low ESR, Vripple_ESR can be neglected for ceramic capacitors, but must be considered if tantalum or electrolytic capacitors are used.

Care must be taken when evaluating a ceramic capacitors derating under dc bias, aging and AC signal. For example, larger form factor capacitors (in 1206 size) have self-resonant frequencies in the range of the switching frequency. So the effective capacitance is significantly lower. The dc bias can also significantly reduce capacitance. Ceramic capacitors can loss as much as 50% of its capacitance at its rated voltage. Therefore, leave the margin on the voltage rating to ensure adequate capacitance at the required output voltage.

The capacitor in the range of 1 μF to 4.7 μF is recommended for input side. The output requires a capacitor in the range of 1 μF to 10 μF. The output capacitor affects the loop stability of the boost regulator. If the output capacitor is below the range, the boost regulator can potentially become unstable.

The popular vendors for high value ceramic capacitors are:

TDK (http://www.component.tdk.com/components.php)

Murata (http://www.murata.com/cap/index.html)