thx all of you
that solved the problem 

Sinces nobody understud what i meant the firs time, im going to rewrite the topic:
 
 The LM35, is a termic sensor that lets 10mV pass tru it for each 1ºC
if the sensor is put in a place where the temperature is 25ºC, hes analogic output will be set to 250mV (not sure if realy millivolts)

what i need is, using this sensor, i want to convert this analog imput into a digital output (A/D conversor)
lets say that i use the digital outputs from a arduino from 0 down to 7, and the temperature is 23ºC

23 to binary => 00010011,
so the output should be:
L, L, L, H, L, L, H and H
(L = low, H = High).
if 25ºC: 00010101
and so on


srry for bad inglish