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 Semiconductor’s 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 bandgap 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