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Inquiries regarding THERMAL INFORMATION on SN65HVD101

Other Parts Discussed in Thread: SN65HVD101

Hello, all

Now we have one inquiries regarding THERMAL INFORMATION on SN65HVD101 from our customer.

Please refer to the item below, and feedback us with your comment.

When referring THERMAL INFORMATION on datasheet page 4 (SLLSE84A), the parameters θJA, θJCtop, ψJT and ψJB are described.

However, since we could not fully understand the relationship between them, please let us clarify

1) why θJA is higher than θJCtop

2) what are ψJT and ψJB are aimed for

We thank you in advance for your information. 

Best regards,

  • Hello Atsushi,

    Thank you for your inquiry. I am moving this post to the Industrial Interface Forum so that a qualified expert for this part can answer your question.

    Thank you,

    Jared

  • Hello Okui-san,

    ThetaJA is the thermal resistance from the die to the ambient air, while ThetaJC is the thermal resistance from the die to the top of the device's packaging. These parameters have different values due to the different levels of thermal coupling from die-to-air compared to die-to-package. As a result, typically the top of the device and the ambient air will be at different temperatures. (There is normally better thermal conductivity from the die to the top of the package, and so the ThetaJC resistance value will typically be higher and the case temperature will be higher than the air temperature.)

    PsiJT and PsiJB are both parameters that are used to relate the amount of power dissipation to the temperature difference between the device's die and another point in the system. PsiJT is referenced to the top of the device's package, while PsiJB is referenced to a location on the PCB near the device.

    For more information, you can refer to this application note on TI's thermal parameters:

    www.ti.com/.../spra953b.pdf

    Please let me know if you have any other questions.

    Best regards,
    Max