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LM27341, TPS54521, LP2998 recommend operating ambient temperature

Winnie Chan94
Intellectual 300 points
Other Parts Discussed in Thread: LP2998, TPS54521, LM27341

Hi,

I have a project design for operating up to 95°C ambient temp, so want to make sure the spec of LM27341, TPS54521 and LP2998 can meet my request. is there have recommend operating ambient temperature information about LM27341, TPS54521 and LP2998?

Thanks!

  • 0
    TI__Genius 16025 points
    Hi Winnie,

    Allow me to forward your question to the appropriate forum for the parts listed.

    Thanks,
    Anston
  • 0 in reply to Anston Lobo
    TI__Guru**** 191445 points
    For TPS54521 (and probably the others as well), only the maximum operating junction temperature is stated. At Ta = 125 deg. C. You cannot dissipate any power in the IC without Tj going above 125 C. Below that ambient temperature, the amount of allowable power dissipation increases as Ta decreases. Typically on a well designed PCB, you may get full rated power up to about 85 C without derating, but it greatly depends on PCB design and what other power dissipating devices are also present on the PCB, air flow, etc. Normally I would recommend the thermal simulation available inside of Webench, but Webench seems to be broken for TPS54521 right now. I have requested it be fixed.
  • 0
    TI__Intellectual 2010 points

    Hi Winnie,

    LP2998 junction temperature range is -40C to 125C. The rise in junction temperature depends on your DDR configuration (PVIN value) and the amount of current. This will give you thhe total power dissipation within the IC. You can then calculate the rise in temperature depending on the package type. 

    Lets call this rise in temperature TA. 

    Now as long as your TA +95C <125C, you will be good. From my experience if you have DDRIII configuration and sourcing /sinking ~1A, you will be well within the datasheet temperature spec.