ADC internal voltage

I have the Arduino Mega 1280
Dear all, what is the maximun voltage I can give the ADC pins for Arduino Mega 1280?

From datashet Vref is aprx 3V, is this the maximun I can give??
Thank you

what is the maximun voltage I can give the ADC pins for Arduino Mega 1280?

It is the supply voltage, in this case it will be 5V max 0V min (no negative voltages).

From datashet Vref is aprx 3V,

No that's not right, it is connected to the supply internally by default.

Tnx