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Thermal simulations


I want to use the HMC461LP3 PA chip and I need to do some thermal simulation so
is it possible to send:

1) thermal properties of the plastic used in the QFN package: Density, Heat
Capacity and Thermal conductivity.

2) The location and areas of the transistors, to know the two areas that are
dissipating power.

Thank you


  • Hello,

    One of our CQEs (Customer Quality Engineer) who supports customers in Europe should soon reply to your question # 1.

    Question # 2 will require some research, so it might take a few days.



  • Hi,

    I used AutoCAD LT to make the die drawing overlay the assembly drawing, then to make rectangles overlay both to indicate the locations and perimeters of the FETs. The FETs are indicated by the two rectangles near the center of the drawing.

    I'll follow up with CQE to ask if they have answers regarding the properties of the package.



  • Thank you SMcBride for you reply, it was really nice of you, but:

    1) There is no FET transistors in the amplifiers. If you look to the data sheet you will that it´s a HBT transistor

    2) The HMC461LP3 PA uses a multi-finger transistor so the area that is dissipating heat is not so small

  • You're welcome, I'm glad to help.

    1) You are correct in having stated that the amplifier contains HBTs, not FETs. However, whether the devices contained are FETs or HBTs distracts from the meaningfulness of your question (i.e., the thermal details) and instead brings this discussion to the level of discussing semantics. I have time for discussing semantics only when it's relevant to the question at hand...thus I stop here...unless you can (please) educate me on the relevance.

    2) You are correct in having stated that the transistors are of the multi-finger variety. However, you requested "The location and areas of the transistors, to know the two areas that are dissipating power." I provided you with those two areas as defined by the outer perimeters of the two multi-finger transistors. Did you intend to ask for something different than what was provided?



  • Though CQE has not yet replied with an answer to question #1, I have found information that you may find relevant for determining the thermal properties of the package material(s). Please see link below:



  • This question has been assumed as answered either offline via email or with a multi-part answer. This question has now been closed out. If you have an inquiry related to this topic please post a new question in the applicable product forum.

    Thank you,
    EZ Admin