Maximum voltage VIN-Pin

Hey there

I'm new here - "hello to all". The Arduino Mega 2560 is my new toy, so I'll try some funny things with it. My first Project will be the stabilisation of my Cablecam. http://www.youtube.com/watch?v=kK8Zw_2M3RM It's already quite stable but that tiny little thing witch makes it 100% usefull isn't developped. So I bought as told the Mega2560 to set this up. My Problem is now, that from the motordriver (BEC port http://www.robbe.de/roxxy-blcontrol-960-6.html) comes 5.5V. Can I just connect to the VIN Pin and forgett about that half voltage or shuld I connect it with the normal input port. Witch range of input voltage can Arduino support?

Greetings from Frankfurt (Ger)

Noctis

5.5V is too high to connect to the +5V pin since the ATmega chip probably has a maximum input voltage of 5.3V. It is also too low to connect to the Vin pin and get 5V out of the regulator. The voltage regulator has a minimum requirement of 6.0V in to get 5.0V out.

The good news is that if you connect to the Vin line you will probably get 4.5V out of the regulator which will be enough to run at full speed. Note that the analog input pins will then have 4.5V as full scale so you might have to adjust some code.

johnwasser:
5.5V is too high to connect to the +5V pin since the ATmega chip probably has a maximum input voltage of 5.3V.

No, the ATmega can safely tolerate 5.5V (absolute Max is 6V).

johnwasser:
The good news is that if you connect to the Vin line you will probably get 4.5V out of the regulator which will be enough to run at full speed

This doesn’t seem like a good idea at all. Depending on how much current is drawn, the regulator won’t be stable.

[quote author=James C4S link=topic=78752.msg594682#msg594682 date=1321114890]

johnwasser: 5.5V is too high to connect to the +5V pin since the ATmega chip probably has a maximum input voltage of 5.3V.

No, the ATmega can safely tolerate 5.5V (absolute Max is 6V). [/quote]

Excellent! So you can just hook the 5.5V to the +5V pin.

thanks a lot!

so, if the input voltage is 5.5V, the complete system will run at 5.5V, right? Is there any safety option if i use the higher voltage wicht provides the ATmega from damage?

Anything over 6V will damage it. Operating at 5V5 is not recommended although it will work. The maximum input voltage is 0.5V above the supply voltage.

you could simply fit a silicon diode in series with the 5v5 and that'll drop it to around 4v8 which should be adequate to drive the chip.