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SN74LVT8996: SN74LVT8996

Eric Cui13
Intellectual 920 points
Part Number: SN74LVT8996

 

1. What  is the maximum junction temperature and  θjc  of SN74LVT8996.

 

2. How to calculate?

  • 0
    TI__Guru 62930 points
    Eric,
    This device has an absolute max junction temperature of 150c.

    The icc parameter in the datasheet shows a max current of 20ma. Assumes all other inputs are biased to VCC or ground.

    This is 0.02 * 3.3 = 66mW.
    Using this with the thermal metric for Theta Ja (worst case PW package) 88degrees/Watt
    88*0.066 = 5.8degrees.

    This is likely not very conservative, as it is not including output loading. However, it is so small that the temperature rise is minimal.
    If operating at max temp of 85c, the junction temp would only be 91c.

    If this answers your question, please click "Verify it as the answer"
    Regards,
    Wade
  • 0 in reply to Wade Vonbergen
    Intellectual 920 points
    Hi Wade,

    I understand that the Tj will be 91 degC assuming the board temperature is at 85 degC but my operating conditions is much harsher than 85 degC due to ambient cool conditions therefore I would need need to know either the theta jc or Tcase maximum temperature.

    Does TI have these information?

    The main heat source is not the SN74LVT8996 but I need to make sure the surrounding heat source does not kill this component.

    Regards,
    Eric
  • 0 in reply to Eric Cui13
    TI__Guru 62930 points
    Eric,
    I can request to have the new standard thermal metrics to be generated.
    This will add theta Jc, and psi Jb among other metrics.
    These will be usable to estimate junction temperature from board or case temp.

    I will submit the request this morning. The typical turn time for is 1-2 weeks.
    Regards,
    Wade
  • 0 in reply to Wade Vonbergen
    TI__Guru 62930 points
    Good news. The modelling team was able to generate metrics quickly.
    Here are the values.
    PW package
    Result- Theta JA-High K : 82.4
    Result-Theta JC, top : 25.7
    Result-Theta JB : 38.1
    Result- Psi JT : 1.2
    Result- Psi JB : 37.7


    DW package

    Result- Theta JA-High K : 61.0
    Result-Theta JC, top : 31.2
    Result-Theta JB : 31.0
    Result- Psi JT : 8.9
    Result- Psi JB : 30.7

    These will be added to datasheet at next update.
    Regards,
    Wade