Configure L200c for 12v input, 5v output

Hi guys, i wonder if someone here can help me out. Im working on a modification for my iPod dock so that it will charge the new iPod Touch 2nd Gen. Previously iPods charged via a 12v line, the latest versions charge via a 5v line. Thus i need to step down my 12v to 5v, i have purchased a L200c adjustable voltage regulator. Can somebody please advise me on how to configure this for my needs as im completely baffled by the datasheet!

Original thread can be found here for reference http://forum.allaboutcircuits.com/showthread.php?t=17729&highlight=ipod

Thanks Guys

Phil

the L200 is an adjustable voltage regulator with adjustable current limiting. a normal regulator will deliver as much current as needed until it reaches its maximum, whereas the L200 can hav a preset current limit lower than it's maximum current output. it does this by reducing its output voltage when the current limit is reached ( I = V/R )

for your application, a simple 5volt regulator will work (L7805), but if u want to use L200, fig1 in the datasheet is what you want. R2 adjusts voltage output while R3 limits current.

Here is a link to the application Notes which explains things a bit better.
I don't know what the current requirements are for your charger/player but the formula for calculating it are also in the App. Notes.

Application Notes for the L200 Voltage regulator