[sdiy] SMD resistors

[clark at andrews.edu]

> I'm going to use a 1206 package with four 603 resistors inside with a
> power rating of 1/16W per element. That's 1/4 W for the whole package.
>
> How hot will it get at the maximum power?

   Very hot.  Probably too hot to touch.  It is NOT a good idea to run SMD
parts at full power.  Ideally the max I'd run them is at half-power.  I
have a board that I manufacture that is a high-powered IR transmitter
array and on it I have two IR chains driven by 3 1210's in parallel. 
At half-power (1/8 watt per resistor) they are very warm to the touch,
almost hot.
   The larger the surface area, the better, since heat will be able to
dissipate faster.
   So my advice is to skip the 0603's if at all possible.  One 1206 would
be FAR better, but I'd seriously consider an array.

   Good luck!

   Tony

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