The LM1117 is a series of low dropout voltage regulators with a dropout of 1.2V at 800mA of load current. It has the same pin-out as National Semiconductors Industry standard LM317.
The Lm1117 is available in an adjustable version, which can set the output voltage from 1.25V to 13.8V with only two external resistors. In Addition, it is also available in five fixed voltages, 1.8V, 2.5V, 2.85V, 3.3V, and 5V. The LM1117 offers current limiting and thermal shutdown. Its circuit includes a zener trimmed band gap reference to assure output voltage accuracy to within ±1%.
The LM1117 series is available in LLP, TO-263, SOT-223, TO-220, and TO-252 D-PAK packages. A minimum of 10µF tantalum capacitor is required at the output to improve the
transient response and stability.
Documents:
http://www.ti.com/lit/ds/symlink/lm1117-n.pdf