I think you are better off with the LM335 as it's output is 10mv/deg K. The LM35 is 10mv/deg.c. There is going to be a problem with the accuracy below 0 deg C. when using the LM35. If you would like rather than analog you could use a TMP-03/04 from Analog Devices which is a pulse width output. I have used these before and work quite well. Just a thought...