5v to 3.3v - Convert 5 Volts TTL signal to the 3.3 Volts CMOS interface 1/5

How to Convert 5 Volts TTL signal to the 3.3 Volts CMOS interface

.from: http://forum.allaboutcircuits.com/showthread.php?t=17057

I have a microcontroller working on 5V, which is directly connected to a sensor working on 3.3v for data communication. Can somebody give an idea about how to connect a mixed 3.3v and 5V different systems? Is there any IC available for level shifting from 5V to 3.3V? 

Solution 1:

http://www.national.com/mpf/LM/LM2937-3.3.html

Solution 2:

You can use the BC547 but you can use also a buffer or NOT gate with open collector output.