SLVSAX2B September   2011  – June 2020 TPS61170-Q1

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Typical Application
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin 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 Switching Characteristics
    7. 6.7 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-up
      2. 7.3.2 Overcurrent Protection
      3. 7.3.3 Undervoltage Lockout
      4. 7.3.4 Thermal Shutdown
      5. 7.3.5 Enable and Shutdown
    4. 7.4 Device Functional Modes
      1. 7.4.1 PWM Program Mode
      2. 7.4.2 1-Wire Program Mode
      3. 7.4.3 EasyScale
    5. 7.5 Programming
      1. 7.5.1 Feedback Reference Program Mode Selection
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 12-V to 24-V DC-DC Power Conversion
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
          1. 8.2.1.2.1 Program Output Voltage
          2. 8.2.1.2.2 Maximum Output Current
          3. 8.2.1.2.3 Switch Duty Cycle
          4. 8.2.1.2.4 Inductor Selection
          5. 8.2.1.2.5 Schottky Diode Selection
          6. 8.2.1.2.6 Compensation Capacitor Selection
          7. 8.2.1.2.7 Input and Output Capacitor Selection
        3. 8.2.1.3 Application Curve
      2. 8.2.2 5-V to 12-V DC-DC Power Conversion With Programmable Feedback Reference Voltage
      3. 8.2.3 12-V SEPIC (Buck-Boost) Converter
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
    3. 10.3 Thermal Considerations
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Third-Party Products Disclaimer
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 Support Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

10.3 Thermal Considerations

The maximum IC junction temperature should be restricted to 125°C under normal operating conditions. This restriction limits the power dissipation of the TPS61170-Q1. Calculate the maximum allowable dissipation, PD(max), and keep the actual dissipation less than or equal to PD(max). The maximum-power-dissipation limit is determined using Equation 14:

Equation 14. TPS61170-Q1 q8_pdm_lvs791.png

where

  • TA is the maximum ambient temperature for the application.
  • RθJA is the thermal resistance junction-to-ambient given in the Thermal Information table.

The TPS61170-Q1 comes in a thermally enhanced SON package. This package includes a thermal pad that improves the thermal capabilities of the package. The RθJA of the SON package greatly depends on the PCB layout and thermal pad connection. The thermal pad must be soldered to the analog ground on the PCB. Using thermal vias underneath the thermal pad as illustrated in the layout example. Also see the QFN/SON PCB Attachment application report (SLUA271).