Thanks for the quick reply! 
I am trying to control a RC car, I have stripped the circuit and I am building my own with an arduino and a Dual H-Bridge, I am unsure of the operating volatge of the motors tho, as they are embedded in the chasis and I do not wanna remove them. Thet were ariginally powered with 3.2V from 2 x AA batteries. I plan to power them with 5V tho.
I am using a 9V battery to power the Arduino and I would like to use the arduino's 5V supply to power the IC and the motors but I do not want to melt my Arduino.
If i make an estimate of 400mA @ 5V, as the demand for my system, this means that the limiter will need to dissapate 1.6W.... Which maybe an issue. But If I use 4/5 x AA, i might be ok?