The LM2267x/LM22680 Simple Switcher Step-Down Regulator Series is the next generation of highly popular LM267x Simple Switcher Regulators. Numerous enhancements and improvements have been added such as an input range down to 4.5V, tighter output accuracy, adjustable switching frequency, a precision enable, and thermally enhanced green packages.
LM2267x/LM22680 Simple Switcher Series - [Link]
http://www.electronics-lab.com/blog/?p=3171