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DAC5675A: Rated Power Dissipation and Junction Temperature

Eddie Lin
Prodigy 20 points
Part Number: DAC5675A

Hi, 

I am using the DAC5675A (5962-0720401VXC) and noticed that power dissipation is not listed in the absolute max ratings section. However, I do see a power dissipation listed in the DC Electrical Characteristics section (specifically, under the power supply section). This is listed as 900mW max for AVDD = 3.3V, DVDD = 3.3V.

My questions are:

1. I am assuming the 900mW power dissipation refers to the power being dissipated by the device at the listed operating conditions. It is NOT a rated power dissipation. Is that correct?

2. (If my assumption in #1 is correct) Is there a rated power dissipation for this device? 

3. Similarly, I also see that a rated junction temperature is not listed in the spec. Is there a rated junction temperature for this device?

  • 0
    TI__Mastermind 18125 points

    Hi Eddie, regarding your questions:

    1. The typical value is what is measured for the listed operating conditions mode. The max value is listed typically as 10-20% higher than the highest power consumption we measure for the device across all supported ambient temperatures, and also across all modes for devices which support multiple modes. This provides plenty of overhead for system design.  
    2. See answer 1 above.
    3. Using the thermal characteristics for the package, you can back calculate the junction temperature by assuming operation at the max power dissipation (900mW) and at the max ambient temperature (+85C). Please refer to this document for assistance in doing so: www.ti.com/.../slua844b.pdf

    Regards, Chase

  • 0 in reply to Chase W
    Prodigy 20 points

    Hi Chase,

    Thank you for the reply. I now understand the 900mW value is a measured value at the listed operating conditions mode.

    My follow-up question is: is there a known rated power dissipation for this device, in other words, a power dissipation at which the part may be damaged?

    The reason I ask is because I need to demonstrate margin between this rated power dissipation and what we actually use the device at.

    Let me know, thanks!

  • +1 in reply to Eddie Lin
    TI__Mastermind 18125 points

    Hi Eddie,

    By my last post, I am intending to say that the device will never operate at more than ~90% of this 900mW metric. The additional overhead is for system designer to add sufficient overhead into the design of the power tree. We cannot guarantee anything beyond this max limit as it may have a lot to do with lot to lot and/or die to die variation. I suggest you carry forward assuming 900mW is the maximum supported dissipation.

    Regards, Chase

  • 0 in reply to Chase W
    Prodigy 20 points

    Thank you Chase.