http://products.cui.com/CUI_V7805-500_Datasheet.pdf?fileID=2982
http://products.cui.com/CUI_V7805-1000_Datasheet.pdf?fileID=5694
http://www.recom-international.com/pdf/Innoline/R-78AAxx-0.5_SMD.pdf
If you're using Analog on your board be careful, these are more prone to produce noise and possibly EMI. Highly recommend running a separate LDO (Low DropOut) Linear Voltage Regulator cascaded from your DC-DC Conv to supply your Analog In, if not two, one for Analog, one for Digital.
SEPARATE YOUR ANALOG GROUND PLANE and have it only connect with the rest of the circuit at the power source.
There is voodoo afoot with DC-DC conv, your component placing has to be precise, your inductor just right, built in shielding with these drop ins is worth the trouble.
Let me tell you, sourcing inductors alone is easily worth it to save the hassle. I have found datasheets recommend obsolete inductors. At least you have the specs but still... Voodoo.
Oh, and don't forget to follow Atmel's app notes on putting an inductor or at least a ferrite bead on your AVCC and DVCC.