• State Resolved
  • Locked Locked
  • Replies 6 replies
  • Subscribers 99 subscribers
  • Views 1108 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

The DM8148 crystal temperature

Alex Timoshenko
Prodigy 130 points

Dear Sirs.

My custom board based on DM8148 has bad work temperature.

I have added additional aluminium radiator.

For 1Ghz with 1.352V core supply the radiator temperature is approx 45 degress. (edited 01/09/2013)

For 600Mhz and 1.1V core supply the radiator temperature is approx 32 degress. (edited 01/09/2013)

The room temperature is approx 25 degress.

Is it normal situation?

Thanks.

Regards,

Alex

  • 0
    TI__Genius 15310 points

    Hi Alex,

    Temperature will increase with increased operating voltage and with increased operating frequency.

    We do not have specific temperature information, but can point you to this footnote at the bottom of the DM8148 Datasheet, Section 6.2 Recommended Operating Conditions:

    (5) For more detailed information on estimating junction temps within systems, see the IC Package Thermal Metrics Application Report

    (Literature Number: SPRA953).

     

    The DM8148 commercial temperature range is 0-90C.  TI guarantees that the product will operate properly within this range.

    BR,

    Viet

  • 0 in reply to Viet Dinh
    Prodigy 130 points

    Hello Viet,

    Thanks for reply.

    Device works fine without additional radiator for 600Mhz. The crystal temperature in this case is approx 53 degress.

    Is it normal?

    Maybe I have internal shortcircuit on PCB or something else...  For example, on Mistralsolution DM8148 board I didn't see radiator (but 4 mounting holes for radiator are available). Do you have radiator on your development board?

    Does DM8148 crystal has onboard protection (thermal shutdown)? Or internal temperature sensor...? How I can provide device thermal protection without additional sensors?

    Regards,
    Alex

  • 0
    Intellectual 580 points

    Hi Alex

    There are  types of heat sensor devices did you try with that.

    Regards

    Asif

  • 0 in reply to Mohamed Asif
    Prodigy 130 points

    Hi Mohamed,

    You right, the are many temperature sensors exist, but much more better to have some internal sensor. Unfortunately I didn't find any information in DM8148 datasheets. I think this crystal doesn't have thermal sensor.

    I have found same post on TI community: http://e2e.ti.com/support/dsp/davinci_digital_media_processors/f/716/t/210819.aspx  and it looks like question about CPU heating is still open.

    For me it is no problem to mount additional radiator on each board, even more, I already have added mount holes for radiator to my PCB.

    How many Watts I should to dissipate into the air for different CPU load stages? - this is critical information for me.

    For now 1.35V and 3.5A gives approx 5W. This is really large value for ARM 1Ghz CPU. Maybe it bad example, but BF561 has 1W consumption (dual core, 600Mhz each).

    I think, device with heating up to 5W (on 4 square cm surface)  and up to 90 degress recommend work temperature, should have internal thermal protection... like PC CPU.

    Maybe I'm wrong...

    Thanks.

  • 0 in reply to Alex Timoshenko
    TI__Genius 15310 points

    Hi Alex,

    Our Product Engineer confirms there is no internal thermal sensor in DM814x.

    BR, Viet

  • 0 in reply to Viet Dinh
    Prodigy 130 points

    Hi Viet,

    Thanks for reply.

    I will try to use some external temperature sensor...

    It would be great if you will add temperature sensor into next crystal releases. I think it would be good feature for all devices based on DM814x.

    I think crystal should shutdown or change current CPU frequency to prevent self-demage . Any case, to repair device by resoldering BGA for a 28x28 balls is impossible.

    Thanks.

    Regards,

    Alex