Ive been wondering what these type of chips are?
and how do they go mounted on a pcb? since there are no pins..i am guessing they are not DIY friendly and the name of such package type?
These are called QFN's (quad flat no-lead) packages, and they are not particularly DIY friendly. They reflow fairly well though. Also, if you can solder the main center pad down (with paste and reflow), you can often solder (carefully) the leads if they wrap up around the sides.
Definitely advanced work though.
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yeah sounds like i'd burn a few before getting it right, hopefully i dont ever need something that only comes in this package at least anytime soon. I opened a cell phone and most of what i saw where these babies thats why i asked
It's actually very easy to solder such a chip if you have the right tools. (I do that at work a lot.) I would go as far as to say that it's easier to solder a QFN using good equipment than it is to solder a SOIC using bad equipment.