alex52:
I just tried to find one on the internet but no luck so far. The name of this sensor is the YL-69.But the analog pin deliver 5V?
Why would you use an analogue output? A digital pin supplies 5V. (Absolute maximum 40mA, so up to about 30mA would be fine. (I'm assuming that the sensor needs a 5V supply voltage.)
You just need to ascertain how much current the sensor uses. You could use a 1Ω to 10Ω resistor in series between the +5V and the sensor's Vcc pin, then measure the voltage developed across it to determine the sensor's current consumption. I = V / R
Edit: Where did you buy the YL-69? They might have the specs.