SNOAA61A October   2020  – February 2021 LMG3422R030 , LMG3422R050 , LMG3425R030 , LMG3425R050

 

  1.   Trademarks
  2. 1Introduction
  3. 2New QFN 12x12 Package
  4. 3Bottom-Side Cooling Configuration and Definition of RθJC/P
    1. 3.1 Definition of RθJC/P for Package Thermal Performance
    2. 3.2 Design Recommendations for Bottom-Side Cooling System
  5. 4Simulation Models and Results
    1. 4.1 Finite Element Models for Thermal Analysis
    2. 4.2 Thermal Simulation Results
  6. 5Experimental Setup and RθJC/P Testing Results
  7. 6Thermal Performance of QFN 12x12 Package on Half-Bridge Evaluation Board
  8. 7Summary
  9. 8References
  10. 9Revision History

7 Summary

Package thermal performance of power devices is equally important as its mechanical and electrical characteristics impacting system efficiency, reliability, and power density. In power applications where the heat dissipation is the utmost requirement, it becomes even more critical for market adoption. The simulation results have demonstrated that RθJC/P value of TI’s new QFN 12x12 package is 45% lower than that of its previous QFN 8x8 package for the same 50-mΩ product. Additionally, TI’s 50-mΩ GaN power stage in QFN 12x12 package shows about 16% less RθJC/P than competitors’ 600-V and 650-V discrete devices of similar on-resistance enclosed in a TOLL or D2PAK package. Experimental testing results show less than 8% difference from simulation outcomes. A particular use case was presented based on a half-bridge design using LMG3422R030 devices. The synchronous buck converter running at 4-kW power was demonstrated with a measured case temperature of 99.3 oC on top of the high-side device package. While switching at high speed and high frequency with integrated protections, TI’s high-voltage GaN power stages in the new QFN 12x12 package can release more power out of this wide-bandgap semiconductor for applications requiring system-size reduction and power-density, power-efficiency enhancement.