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TMS320C6748: Junction temperature of processor

Archana Rao
Intellectual 915 points

Part Number: TMS320C6748

Hi,

We are using TMS320C6748EZWTD4 DSP in our design.

The maximum junction temperature of this device is +90 deg C.

This DSP sits in a product where the ambient may exceed +70 deg C and air flow over this chip is nil.

This chip operates at 442 MHz core with 89% utilization.  With power estimator sheet, we were getting power consumption around 0.65W.

Due to +70 deg C requirement, this chip is failing in our thermal analysis.  Can you please let us know what would be the behavior of this chip if the junction temperature crosses +90 deg C for short and long duration?

Regards,

Archana Rao

  • 0
    TI__Guru 50170 points

    Hi,

    The device must be kept below the maximum rated temperature at all times. Operation above this temperature will reduce the device’s reliability and may cause it to fail. A thermal solution will be needed to remove the heat from the device when operating at the maximum ambient temperature. Since there is no airflow, is the board in a sealed enclosure?  Can a thermal pad be used to transfer the heat from the device to the enclosure?  Alternately, is there room in the enclosure for convection cooling with a heat sink?  The enclosure may then need fins or a means to transfer heat to an attached structure. 

  • 0 in reply to Rex Chang
    Prodigy 20 points

    Hi Rex,

    The board is in sealed enclosure. Heat sink or thermal pad is possible to increase the reliability. Can you tell which surface will dissipate heat solder leads side or package structure side. What side is recommended to plan a thermal pad.

    Another question is what exactly goes fail inside the IC. I believe similar device with high temperature range support lower frequency of operation which is logical. So as per my understanding whole device may not get damage as it supports till 105 deg C.

    More explanation will help.

  • 0 in reply to Ratnesh Gaur
    TI__Guru* 85095 points

    >>Another question is what exactly goes fail inside the IC. I believe similar device with high temperature range support lower frequency of operation which is logical. So as per my understanding whole device may not get damage as it supports till 105 deg C.

    Ratnesh - if you are not operating within the recommended temperature specification you are in violation of the datasheet specifications - TI cannot guarantee long term reliability , operations and timings. The parts may only be getting tested in the range specified and running them beyond the spec - you are on your own. Other aspect is power on hours and electro-migration for running at higher then specified temperature.

    you can find some basics on that in the following application note

    https://www.ti.com/lit/an/sprabx4a/sprabx4a.pdf

    Although it should be noted that we do not have similar data for this device family