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LM117HVQML-SP: LM117H MDE thermal resistance

David Ben Chamo
Prodigy 85 points
Part Number: LM117HVQML-SP
Other Parts Discussed in Thread: LM117QML, LM117QML-SP

hello

i have a few more questions about regulator LM117H MDE.

1. what is the thermal resistance of LM117H MDE as it in DIE configuration ?

2.is the junction temperature is the unique factor of MTBF? ( for junction temperature analysis , have been taken power dissipation , ambient temperature and heat sink )

3.in datasheet named LM117QML,LM117QML-SP pg. 15 according figure 6 , is it can be possible to pull from single LM117H MDE 800mA ,in conditions of : Vin-Vout=2.5V , Tjunction=100C  ?

3.is there a difference between the die's on LM117H family and the LM117K family?

4.is there is difference between LM117H MDE and LM117H MD8  , in case of thermal resistance specific and in general?

best regards.

david

  • 0
    TI__Mastermind 20045 points
    Hi David,

    1. I will have to look into this. I would imagine if you attach the die to the board with thermal epoxy the thermal resistance from die to board would be near 0.
    2. I will look into this and get back to you.
    3. It looks like this may be possible. However, note that this graph is for typical characteristics, not a maximum or minimum. If you need 800mA you would be better off looking at the T, S, or K packaged devices.
    4. I will look into this with the first question.

    Thanks,
    Kyle
  • 0 in reply to Kyle Rakos
    TI__Mastermind 20045 points

    Hello David,

    I have found out the following additional information.

    1. The die itself has thermal resistivity of silicon.  The values that TI uses for thermal modeling are 117.5W/(M*K) Base resistance at a Tref of 100°C and a temperature dependence coefficient of -0.42W/(M*k^2).

    2. Higher junction temperature will result in a higher failure rate versus a fixed total power-on hours or a lower lifetime at a fixed failure rate.  See JEDEC JESD85 “Methods for Calculating Failure Rates in Units of FITs” and www.ti.com/support-quality/reliability/reliability-terminology.html 

    The thermal properties for the die are the same. MDE denotes Die, Space Level ELDRS Radiation Tested and MD8 denotes products processed to Level B military wafer fab standards and visual criteria.

    Thanks,

    Kyle