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TPS53219A: operating temperature range

Toshiro Imi
Expert 6350 points
Part Number: TPS53219A

Hello,

Our customer has a question about operating temperature range. In his application, he measured the worst case temperature on package top raised up to 88.5C though the specification is guaranteed up to 85C TA. Even if this is not exceeded 150C Tj  according to him, would you let us know if it has potential issue.

I simply think that some specifications may violate because TA is out of spec condition.

Best regards,

  • 0
    TI__Mastermind 29410 points

    Hello Toshiro, 

    The device junction temperature is 150C. having the case temperature at 88.5C, I am assuming your ambient is less than 88.5C, can you please confirm? you may still have a good margin  to to reach the junction of 150C. 

    What is you wost case power losses  and the ambient temps in you applications? 

    We can estimate the junction temps from that  using the thermal metric below 

    Thanks!

    Tahar

  • 0 in reply to Tahar Allag
    TI__Expert 6350 points

    Hello, Allag,

    Thank you very much for our help.

    We discussed how we can measure the ambient temperature in his test board. However the customer is annoyed ambient temperature measurement location.

    Could you let us know which measurement point is the best, either the highest ambient temperature location, lowest or middle point even though the temperature gap may be not so much.

    Best regards,

  • 0 in reply to Toshiro Imi
    TI__Mastermind 29410 points

    Hello Toshiro, 

    focus on the point in where the temp is the highest just as shown below

    Thanks!

    Tahar

  • 0 in reply to Tahar Allag
    TI__Expert 6350 points

    Hi Tahar,

    Thank you for your reply. The customer asked that he wants to know which location was the highest ambient temperature in your test case.

    Best regards,

  • 0 in reply to Toshiro Imi
    TI__Mastermind 29410 points

    Hello Toshiro, 

    To make sure that there is no confusion in the naming, ambient temp and is the outside temperature applied to the device. for example, if we are testing the device in the lab without airflow, than the ambient temp is the the lab room temperature. 

    case temperature if the the temperature measured using thermal camera and pointed at the center of the device as shown below

     

    and than junction temperature can be estimated using the below equations 

    Junction Temp = Case Temp + Psi JT x Device Power

    Note that Theta JC is NOT the right parameter to use for this analysis

    For more details, check out the thermal application note here:

    https://www.ti.com/lit/an/slua844b/slua844b.pdf?ts=1670871288652&ref_url=https%253A%252F%252Fwww.google.com%252F

    Semiconductor and IC Package Thermal Metrics (Rev. C) (ti.com)

    Thanks!

    Tahar

  • 0 in reply to Tahar Allag
    TI__Expert 6350 points

    Thank you for your suggestion.
    I fully agree with you that an ambient temperature should be a test condition, not measured on the board.
    In this customer case, even though he does not disclose everything e.g. schematics, PCB layout, thermal source, I suppose that TPS53219A was located closely to the thermal source without enough heat sink. So I am wondering that the ambient temperature close to TPS53219A was higher than that. I think this is the reason he will measure the ambient temperature.
    I will feedback to you his measurement data though, can we say that TPS53219A can guarantee the specification if his measurement results from less than 85C. can we also say that TPS53219A can guarantee the specification if Tj is less than 150C even if the ambient temperature is higher than 85C.

  • 0 in reply to Toshiro Imi
    TI__Mastermind 29410 points

    Hello Toshiro, 

    The ambient temperature specifications are mentioned in the EC table and it is at 85C. The device still functional if the ambient is above 85C as long as the Junction is less than 150C.  88C is not too far from 85C, the EC table can still hold as the EC table did not account for the self heating of the device. 

    Thanks 

    Tahar