Thermal resistance psi jt ΨJT of ADP5062

Dear Sir/Madam,

Our customer asked about psi jt ΨJT of your ADP5062 20 Ld LFCSP package.

There is the theta JA and JC on your datasheet table-5.

Do you have the way for calculation of ΨJT?

Technical note or application note?

I could not find it in your web pages well.

Thanks Kaos

  • Thank you for your kindly answer Allustrisimo,

    I already reported with your answer.

    When I get the update, then I will put it here again, thanks again, Kaos.

  • Hi Allustrisimo,

    Our customer replied for your answer.
    Your answer was not the answer what customer expect.

    After know psi-JT, customer would calculate his TJ.

    Customer's purpose:
    After bring the TJ(die junction temp)=die temp by calculation,
    customer would like to confirm that his aplication have been driven by more than 125C(max Operating Junction Temperature Range).

    From your info, customer cannot know the TJ(die temperature).
    (cannot take the temperature at internal of die )

    Customer can bring the PD and TD.
    PD = the add-voltage X comsumption current
    TD = can measure the package surface temp
    but cannot measure the die temperatute.

    So after get your psi-JT, custoer will calculate die temperature(JT).

    How should we fix this?

    Thanks Kaos

  • Thank you Alex

    I reported your comment to our customer already. When I got the additional reply, then I will put it here again.

    Thank you for your kindly support !!! Kaos

  • Hi Alex,

    I just got the reply from our customer.
    But customer didnt satisfy for your answer.

    Simply he say,
    Do you have the value of psi JT of ADP5062 or not?

    Eg; Your ADP5073 show the psi JT on your datasheet.

    Your answer TA and theta-JA come from air, so there is much error.
    And TC and theta-JC are difficult to measure due to there is thr under of package as for TC.

    Thanks Kaos

  • Hi Kaos,

    The ADP5062 data sheet does not provide value for psi-JT, but only theta-JA and theta-JC. If the customer wants to calculate the junction temperature (JT), he may use the formula stated in the equation 5 on page 39/44 of the data sheet which uses the given value for theta-JA or equation 6 if he wants to use theta-JC.

    Since theta-JA and theta-JC are given, you can use these formula below to calculate the junction temperature.

    TJ = TA + (PD × θJA) or  TJ = TC + (PD × θJC)

    If you have any concerns, please let me know.