Systems & Design

Thermal Characterization of Complex Electronics

A basic primer on structure functions.


This whitepaper describes the role of thermal transient measurement to characterize semiconductor thermal behavior. It focuses on the value measurement derived structure functions provide through interpretation of the heat flow path inside a package for use in thermal characterization, failure diagnosis, and improving simulation thermal model accuracy.

Structure functions transform thermal transient measurement results into a thermal resistance versus thermal capacitance profile, which provides detailed thermal information of each layer the heat passes through, from junction to ambient. This enables identification of the physical characteristics of layers such as die attach, base, package, heatsink, and even cooling devices such as a fan.

Topics include:

  • Thermal Transient Measurement Applications
  • Structure Functions: Analyzing the heat flow path from junction to ambient
  • Extracting information from a thermal resistance vs thermal capacitance profile
  • Cauer-Ladder network models and structure functions
  • Cumulative and Derivative Structure Functions – what can they indicate?
  • Appendix: The Math behind converting temperature vs time into a structure function
  • 3 Examples of using Structure Function:
    • Characterizing Interface Resistances – Identifying defects in LED Lighting
    • TIM Material Thermal Characterization
    • Improving Thermal Simulation Component Model Accuracy

To read more, click here.

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