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UCC27524A-Q1: The Junction-Case thermal resistance question

Part Number: UCC27524A-Q1
Other Parts Discussed in Thread: UCC27524


My customer is using UCC27524 as their secondary side low side drivers.

In datasheet, we only give the thermal resistance of Junction-top case, but not give the value of Junction-bottom case.

  • Why does not the datasheet offer the value of thermal resistance of junction-bottom case with SOIC8 package?
  • When the temperature of top side and bottom are different, what is the thermal circuit model look like? How to calculated the junction temperature?
  • As the value of thermal resistance of junction-bottom case is much lower the junction-top side one, so the temperature of bottom side will be lower. Customer wonders that, how to measure the bottom side package temperature of UCC27524? And, the most important, what is the proper way to evaluate the thermal performance of this IC?
  • Hello Shenhua, 

    Thanks for your help promoting our drivers, my name is Mamadou Diallo from the High Power Drivers team.

    There many factors when discussing semiconductors thermal performance including PCB layout, ambient temperature, switching frequency, packaging, etc...

    The thermal models available in the datasheet are a good method to predict the thermal performance of the driver IC given specific conditions. Why is the customer trying to measure the bottom side temperature? I am not sure this will provide you with more accurate performance.

    The links below discuss in detail how to calculate junction temperatures of gate drivers ICs in general and other semiconductor ICs.

    Please let us know if this addresses the customer questions by clicking the green button or further post on this thread.



  • Hello Shenhua,

    I have not heard from you, I will therefore assume this issue is closed and mark this thread as resolved. If so, please press the green button or let us know if you have further questions by further posting on this thread.