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Author Topic: Powering Arduino Ethernet with 5VDC  (Read 398 times)
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Hi,

is it possible to power an Arduino Ethernet directly with 5VDC/GND applied to the 5V/GND pins?
If so, how much mA are required?

Bouni
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Looks like the W5100 Ethernet chip draws up to 183 mA.  The rest of the Arduino draws less than 100 mA so I'd guess about 300 mA should do it.
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Hi john,

i've tried to supply the Arduino with 5V provided by a LM2940 directly to the 5V pin. It works, but the LM2940 gots extremely hot (SOT223 package).
So i decided to use a 78S10 in a TO220 package connected to the Vin pin.

I also found this text in the description of the Arduino Ethernet Board:

Quote
5V. This pin outputs a regulated 5V from the regulator on the board. The board can be supplied with power either from the DC power jack (7 - 12V), the USB connector (5V), or the VIN pin of the board (7-12V). Supplying voltage via the 5V or 3.3V pins bypasses the regulator, and can damage your board. We don't advise it.

I think i use the Vin method in the future.
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If you put more than 6V on the +5V pin you could damage the ATmega.  Always use a REGULATED 5V supply when providing power to the +5V pin

There was some talk of 5V on the +5V pin possibly  damaging the regulator but on reading the regulator specs I think that is only possible when there is a large (1000 mF) capacitor on the 5V line AND the input of the regulator is shorted to ground.
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