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the maximum ambient temperature is 80 degrees C
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If so, you may want some more effective cooling than placing the part in still air...
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Are these components really limited to 1.6W?
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No, see above.
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I would not be able to use even 1/10th of the resources of the chip!
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How did you calculate the power demand in this case?
I know, that you are able to create a design with unusual high average register toggle rate. But I never saw such a design in practice. I mostly over-estimated core power consumption of real designs.