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That does seem to be a bit on the warm side.  However, I will need to check with some of the design team to see if it is unreasonable.

--Bobby

Suggest that your post can be made more compelling by: rerun of your tests under expanded conditions:

a) Baseline - perhaps a 1Hz toggle of 3-4 GPIO (no Leds) no other peripherals (beyond 1 GPIO Port) enabled

b) Selectively enable each of those Peripherals - but only 1 in use @ a time.  Chart & Report

c) You seem "pro-enough" not to run single board test.   Far stronger should you run 2-3 boards thru such testing - report the composite results.  (single board "anomalies" eat time, money, morale (don't ask "how" I know...)  {this reporter has past, "Set-Top-Box" design/develop experience - this is how we tested/verified for consumer product w/ >1M production...}

Reporting data - this format - adds much value to vendor (likely adding interest/support) and alerts you/they to likely "worst offender."

Bon chance...

Thanks for your reply.

I appreciate you suggestions and don't disagree but I simply wanted to find out if the operating temperature I am observing was out of the ordinary or not before embarking on a lengthly study.

The temperature I initially mentioned was not from a single board. This is an average temperature which has consistantly been observered over many boards and is not isolated to one or two.    

scharppe

I simply wanted to find out

You are welcome.  Note that you report a 33°C rise over ambient - very much suspect that a "baseline reading" (as suggested) will prove worthwhile. 

Unstated is if/how you manage air-flow - this can be vital factor.  Further - this reading was taken w/enclosure (if there is one) removed or "opened."  The enclosure may have a rather drastic effect upon your temperature measurement... and management.

Remainder of past post aims to probe & isolate, "hot spots!"  (pun not intended)

Scharppe,

There will be a temperature increase when the device is powered on and running several peripherals. From the peripherals that you listed as on, I would expect up to almost a 20C increase (not a specified or characterized value  The implementation of Ethernet on this class of devices is the main source.  We do not specify the amount the temperature will increase over measured ambient in our data sheets.  The values from your first post seem higher than we would expect.  Of the information that you have provided, I suspect inaccuracy in the IR camera, as well as the ability to isolate the extra heat down to the LM3S6911 device only.   

Lela 

As expected - factory hones in upon MCU - outsiders look to less "insider" solutions. 

Air-flow across the device always helps - as does transferring as much heat as possible from the silicon - into a proper, heavily via'ed pcb.  (via every Gnd, Vdd pin to its mating pcb plane to best "pull" - and better distribute this unwanted heat) 

As Ms. Garofolo states - certain MCU peripherals are more potent/known offenders.  You may be able to "sleep, deep-sleep, or selectively disable" these prime players to reduce dissipation...  And you may be able to lower MCU's System Clock during certain, relaxed intervals.  Going even further - do not call upon the MCU to sink/source any but minimal currents.  (employ a separate device(s))

Minimization of power usage - we past discovered - proves far better than - "after the fact" - heat dissipation tactics...  Heat is no friend to silicon...