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LM1875T/LB05 ESD classification and temp specs

Aaron Spaete
Expert 4275 points
Other Parts Discussed in Thread: LM1875

Team,

I have a customer that is looking to replace the TDA2030H with the LM1875T/LB05.  A few questions came up that need help answering.  

 

1) ESD Classification?

2) Why is it C vs C/W junction to case temperature and junction to ambient temperature?

3) what is considered the case?

I am attaching a snapshot of the datasheet with the clarifications.
LM1875T questions 2015 03 23 .pdf

  • 0
    TI__Guru 52115 points

    Hi Aaron,

    I will try to find the information for you.

    Andy

  • 0
    TI__Guru 52115 points

    Hi Aaron,

    I have got some answers to your questions from my colleague.

    "LM1875 was released a long time ago like. There is no note about ESD related information in abs max rating items.

    I just confirmed this with our QA guy.

     

    1)     There is an guide line as TI as follow.

    For device, Human body model min 1000V and CDM (Charge device model) min 250V

    For device handling ESD environment, we have guide line in our Web.

    Here is the URL as below

    http://focus.ti.com/quality/docs/qualityhome.tsp

    In this page, go down to “Policies & Procedures” and then Click the “General Quality Guideline”

    Then you will get a file named “szzq076f.pdf”. In pg5 item 13, there is an note about ESD. And you will find

    Doc name “JEDEC JESD625” which describe ESD handling environment.

     

    2)     Regarding unit of Pkg thermal resistance, the unit is ℃/W.

    3)     Θjc is specifying thermal resistance of Junction to Case(Metal Tab)

            Θja is specifying thermal resistance of Junction to ambient (via mold)

    4)     My colleague in TIJ QA guy told me that there is doc # “FSC9300124” quality check result report.

    This report is saying, a) LM1875 passed 2000V of ESD, b) You can get this report from SVA QRE by telling the report #"

    Andy

  • 0 in reply to Andy Liu (BMS)
    TI__Expert 4275 points

    Andy,

    Is there reason we don't specify a temp range? My customer needs to uprate the part just to make sure it passes -40 to 85C, which adds cost.

    If the temp could be specified on the datasheet, this would help a lot.

    Regards,
    Aaron

  • 0 in reply to Aaron Spaete
    TI__Guru 52115 points

    Hi Aaron,

    Let me double check with my colleague whether we can still can find any internal document that specifies the temperature range for LM1875. 

    Andy

  • 0 in reply to Andy Liu (BMS)
    TI__Guru 52115 points
    Hi Aaron,

    The operating temperature is not specified on the datasheet. However, the operating temperature depends on supply voltage, load resistor and heat sink thermal resistance.
    Here is an equation about allowable power dissipation.
    Pdmax = (Tjmax-Ta)/(θjc+θca)
    Where
    Pdmax: Maximum allowable power dissipation
    Tjmax: Maximum junction temperature, in this case it is 150 degC
    Ta: Ambient temperature.
    θjc: Junction to case thermal resistance.
    θca: Case to ambient thermal resistance.

    So if this customer knows the maximum power dissipation of their system, they can easily calculate the operating temperature range by this equation. In addition, more details are available on the Page 8 of LM1875 datasheet.

    Andy