JAJSUQ8C June   2024  – September 2024 TPSM81033

ADVANCE INFORMATION  

  1.   1
  2. 1 特長
  3. 2 アプリケーション
  4. 3 概要
  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 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 Undervoltage Lockout
      2. 6.3.2 Enable and Soft Start
      3. 6.3.3 Setting the Output Voltage
      4. 6.3.4 Pass-Through Operation
      5. 6.3.5 Power Good Indicator
      6. 6.3.6 Implement Output Discharge by PG function
      7. 6.3.7 Overvoltage Protection
      8. 6.3.8 Output Short-to-Ground Protection
      9. 6.3.9 Thermal Shutdown
    4. 6.4 Device Functional Modes
      1. 6.4.1 PWM Mode
      2. 6.4.2 Power-Save Mode
  8. 7 Application and Implementation
    1. 7.1 Application Information
    2. 7.2 Typical Application
      1. 7.2.1 Design Requirements
      2. 7.2.2 Detailed Design Procedure
        1. 7.2.2.1 Setting the Output Voltage
        2. 7.2.2.2 Output Capacitor Selection
        3. 7.2.2.3 Input Capacitor Selection
    3. 7.3 Power Supply Recommendations
    4. 7.4 Layout
      1. 7.4.1 Layout Guidelines
      2. 7.4.2 Layout Example
      3. 7.4.3 Thermal Considerations
  9. 8 Device and Documentation Support
    1. 8.1 Device Support
      1. 8.1.1 サード・パーティ製品に関する免責事項
    2. 8.2 ドキュメントの更新通知を受け取る方法
    3. 8.3 サポート・リソース
    4. 8.4 Trademarks
    5. 8.5 静電気放電に関する注意事項
    6. 8.6 用語集
  10. 9 Revision History
  11. 10Mechanical, Packaging, and Orderable Information
    1. 10.1 Mechanical Data

7.4.3 Thermal Considerations

Restrict the maximum IC junction temperature to 125°C under normal operating conditions. Calculate the maximum allowable dissipation, PD(max), and keep the actual power dissipation less than or equal to PD(max). The maximum-power-dissipation limit is determined using Equation 5.

Equation 5. TPSM81033

where

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

The TPSM81033 comes in a QFN package. The real junction-to-ambient thermal resistance of the package greatly depends on the PCB type, layout. Using larger and thicker PCB copper for the power pads (GND, PVIN, and VOUT) to enhance the thermal performance. Using more vias connects the ground plate on the top layer and bottom layer around the IC without solder mask also improves the thermal capability.