Hi,
can someone tell me what chip is used as the 3.3 V voltage regulator on the Arduino FIO board ? What I need to know is how high can the input may go. It works fine at 5 V (when powered from the USB connector), but I would like to know what is the maximum it can withstand.
Thanks
As a rule of thump, a TO-220 case without additional heat sink can dissipate 3 watt, a SOT-23 SMD case around 500 mW.
My take on this rule of thump (or thumb) is only 1 Watt. The thermal resistance of a TO-220 case is about 65 C/W (junction to ambient) so 1W takes you 65 degrees above ambient, or 90C if ambient is 25C. That's pretty hot. Above 100C junction temperature parts start failing sooner, but suppose we allow operation to 150C (common absolute maximum). Less 25C for room temperature allows a rise of 125C, and dividing by 65 C/W gives a maximum power dissipation of 1.92W (all without heatsinking).
I would like to respectfully challenge your 3W number 
Unfortunately none of this serves to answer the poster's question, but I am in a picky mood.
To try to answer the poster's question, the Fio web page (http://arduino.cc/en/Main/ArduinoBoardFio) suggests a maximum voltage input of 12V so you are at least good up to that voltage.
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The Quick Shield: breakout all 28 pins to quick-connect terminals
I would like to respectfully challenge your 3W number
Please do! It was an awkward typo. It should read 1 - this is absolutely correct! - and the "p" should be a "b" as well
Values WITH heatsink are considerably higher of course. 100 W have been reported for TO-220 with huge heatsinks and perfect thermal coupling...
Always a good practice to deal with proper heat management, however most linear regulators have a back-up shutdown protection mode if heat dissipation or over current condition arise?
Lefty
RuggedCircuits,
To try to answer the poster's question, the Fio web page (http://arduino.cc/en/Main/ArduinoBoardFio) suggests a maximum voltage input of 12V
:-[ Shame on me, I missed that !
deSilva,
the regulator package is not TO-220 ( 3 pins), but SOT-23-5 (5 pins), like the GS2915LF regulator. I found a few of these on Internet, and they all accept 6.5 V max, so going to 6 V will be safe. Looks like the on used on the FIO board accepts higher voltage. Surface mount chips are fine, but those smaller one are not printed with the chip number.
Thanks to all of you for opening my eyes !!!