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TLC5940-EP: PWP package:Operating Life at Tj=160c

toshifumi iwamoto
Prodigy 10 points
Part Number: TLC5940-EP
Other Parts Discussed in Thread: TLC5940

Tool/software:

Hello,Expert.

The operating life graph(Figure11) in the data sheet does not include a graph for the Tj temperature of 160c in the PWP package. I want to know Estimated Life at Tj=160c.

Could you let me know Estimated Life of PWP ?

  • 0
    TI__Mastermind 20515 points

    Hi Toshifumi,

    Actually, you can see that when the Tj is over than 150C, it will enter into thermal shutdown. In other word, the device will not work in such condition. So, we don't have the life time over than 150C.

    Do you mean you need work over than 150C?

    BR, Jared

  • 0 in reply to Jared Zhou
    Prodigy 10 points

    Thanks for your reply dear BR,Jared.

    I understand reason by your comment.
    I taked miscalculation about TJ temperature.
    I used TLC5940PWP PowerPAD Soldered graph on Figure2,Power Dissipation Rate vs Free-Air Temperature.
    Tj temp became to 160C at Air temp is 64C.So, I asked about Tj is 160C.
    By the way,There are two graph of PWP in Figure2.
    I don't know mean two PWP graph.
    What do you mean PowerPAD Soldered and PowerPAD unsoldered ?
    I did not find "PowerPAD" of keyword in datasheet.
    Is this mean the "Thermal PAD" ?

  • 0 in reply to toshifumi iwamoto
    TI__Mastermind 20515 points

    Hi Toshifumi,

    You are right, I think it means thermal pad.

    BR, Jared

  • 0 in reply to Jared Zhou
    Prodigy 10 points

    Hi Jared,


    Thanks for reply.
    I select PowerPAD soldered.
    I think that Tj temperature become to about 160c on ambient temp=64c by this condition.
    This RθJA value is 34.3c/w.
    Tj=64c+34.3(c/w) x 2.8w=160.04c
    But, when PowerPAD soldered,
    I think that RθJA value reduce to lower than 34.3c/w.
    If you know that value, could you let me know ?

  • 0 in reply to toshifumi iwamoto
    TI__Mastermind 20515 points

    Hi Toshifumi,

    Actually, I don't understand you very well, so I am not sure which value you want to know.

    But can you please tell me how you calculate the 2.8W power for TLC5940?

    BR, Jared

  • 0 in reply to Jared Zhou
    Prodigy 10 points

    Hi Jared-san,

    Thanks for your reply.
    I was sorry that you confued.
    I want to know Operating Life for TLC5940PWP(PowerPAD Soldered) at Free-Air temp is 64C.
    In the Figure 2. Power Dissipation Rate vs Free-Air Temperature, Free-Air temp is 64c.
    The Power Dissipation Rate of PowerPAD soldered of PWP become to 2.8W.

  • 0 in reply to toshifumi iwamoto
    TI__Mastermind 20515 points

    Hi Toshifumi,

    Ok, I see it. You mean the IC is working under the temp (64C) and according to its own power dissipation, the temp will rise to 160C. So you want to know the life time in 160C. Am I correct?

    But my question is when device temp rise to 160C, the device will enter TSD, then the device will not work in this temp.

    Secondly, I think the 2.8W for this device doesn't make sense, so I think you might calculate the power error.

    BR, Jared

  • 0 in reply to Jared Zhou
    Prodigy 10 points

    Hi Jared-san,

    Thanks for your support.
    I could understand scale factor value of power changed by board design.
    This my inquiry is close.
    Thanks!