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MOSFET (Si/SiC) Forum Discussions

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What is the difference between RthJC and RthJA? We see the same value of Rthjc for CoolMOS TO247 package, CoolMOS DPAK and CoolMOS IPAK
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yiye_4841451
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Moderator 5 replies posted Welcome! First reply posted
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RthJC is the thermal impedance between Junction to Case. This is the same irrespective of the package type, except for Full PAK where the mold compound is different / thicker adding thermal impedance. Hence except Full PAK, the remaining packages have the same Rthjc. SOT223 is also an exception, considering a very small package structure. This does not include the heat sink.

RthJA is the thermal impedance between Junction to Ambient. This includes the heat sink. Hence based on the standard heat sink assembly used during device characterization, the RthJA of different packages are different.

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yiye_4841451
Moderator
Moderator 5 replies posted Welcome! First reply posted
Moderator
RthJC is the thermal impedance between Junction to Case. This is the same irrespective of the package type, except for Full PAK where the mold compound is different / thicker adding thermal impedance. Hence except Full PAK, the remaining packages have the same Rthjc. SOT223 is also an exception, considering a very small package structure. This does not include the heat sink.

RthJA is the thermal impedance between Junction to Ambient. This includes the heat sink. Hence based on the standard heat sink assembly used during device characterization, the RthJA of different packages are different.
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