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SN74LVC2T45 - Thermal characteristic Theta JC and TJ (MAX)

Kawai
Guru 19775 points
Other Parts Discussed in Thread: SN74AVC2T245, SN74AVC4T245, SN74LVC2T45

Hi Team,

Our customer requests us the information of the thermal characteristic of SN74LVC2T45YXPR.
Could you provide us the following two information ?

[Q1]
What is Theta JC (Junction to Case) of SN74LVC2T45YZPR ?

[Q2]
What is the maximum junction temperature, TJ MAX ?

Best Regards,
Kawai

  • 0
    TI__Expert 6430 points

    Hi,

    I will check with thermal model team. If I get feedback, I will let you know. If the thermal parameter need to be generated, it will take two weeks in general

    Thanks

  • 0 in reply to Wei Lang
    Prodigy 185 points

    Hi TI Team,

    I am looking for Tj (max) info for SN74AVC2T245 and SN74AVC4T245 which I believe should be the same.

    I am posting in this forum to avoid creating another forum as I suspect the Tj info for SN74LVC2T45 might the same as SN74AVC2T245 and SN74AVC4T245 that I am looking for.

    Thanks.

  • 0 in reply to Wei Lang
    Guru 19775 points

    Hello Wei-san,

    Thank you for your cooperation.

    We look forward to hearing from you soon.

    Best Regards,
    Kawai

  • 0 in reply to Kawai
    TI__Expert 4525 points

    Hello Wei-san,

    Since customer needs the data by 8/1 for evaluation of prot type board, can you kindly follow up getting the date by then?

    Thank you very much for your big help.

    Thank you and best regards,

    Daisuke KAWASAKI

     

  • 0 in reply to daisuke kawasaki
    TI__Expert 6430 points

    Dear All,

    I have ask thermal team to speed up this device request. If I get the data, I will post here.

    Thanks

  • 0 in reply to Wei Lang
    Guru 19775 points

    Hello Wei-san,

    Could you please give us the update about the thermal characteristic ?

    Is there a data for SN74LVC2T45YZPR?

    We would appreciate if you could tell us the current situation.

    Best Regards,
    Kawai

  • 0 in reply to Kawai
    Guru 19775 points

    Wei-san and Team,

    Do you have any progress about the thermal characteristic data ?

    When can we have the information ?

    Best Regards,
    Kawai

  • 0 in reply to Kawai
    TI__Expert 6430 points

    Hi,

    Please refer the below data.

    Theta JA-High K

      105.8 

    Theta JC,   

       1.6

    Theta JB

      10.8

    Psi JT

        3.1

    Psi JB  

        10.8

     

    The maximum junction temperature is not on hand. Could you let customer to estimate the value by following equation:

     

    TJ = TA + ( R θJA × PD )

    where: TA = ambient temperature for the package ( °C )

    R θJA = junction to ambient thermal resistance ( °C / W )

    PD = power dissipation in package (W)

    Thanks

  • 0 in reply to Wei Lang
    Guru 19775 points

    Wei-san,

    We greatly appreciate for the answer. We have additional questions.

    [Question]
    The value of Theta JA is different from the value in the datasheet. Which is the correct value ?

    Your answer : 105.8
    Datasheet : 102

    [Question]
    I could ask our customer the condition of their usage to calculate PD. However,  how can we judge if the device could allow its power dissipation without recommended TJ(MAX) information?

    **Please give us your help as our customer needs to judge the device ASAP.

    I believe this device would not heat up so much, so TJ(MAX) is not listed in the datasheet. Generally the device would not have any problem unless if it is used in the high temperature environment.

    Calculating PD from the datasheet using the equation you gave me on the other thread, PD(worst) would be...

    PD(worst) = 5.5V x 32mA x 2 = 352mW
    TJ = TA + (352mW x 105.8) = TA + 37.24

    If TJ(MAX) is 125C, the device could be used in TA<87C.

    Best Regards,
    Kawai