This is a 1A Adjustable SOT-223 voltage regulator capable of outputting 1.2V to 18V.
The LM1117 uses the same pin-out and setup as the popular LM317 adjustable regulator, contained in a handy surface mount package.
Requires two external resistors to function.

Documents:

• FAN1117A.pdf
• SFE Eagle Library has this part!
• Check out Sparkfun's Unregulated Power Supply Tutorial