eloso: I'm using linear regulator because it is easy to make and it is only a school project. So i will only use it once. I already have a big heatsink and thermal paste so generating heat is not a problem.
I think you under-estimate how hot a regulator will get passing 1.5A of current. I'm too lazy to do the math, but if it's dropping any voltage whatsoever, it may be impractical to keep the die temperature cool enough to survive. I built a 28v-to-15v regulator to supply 100mA or so of current, and the little 1"x2"x0.5" heatsinks got hot enough that I couldn't touch them comfortably. You're asking for a lot more current than that. Trust me -- that "1.5A" spec on the regulator is nothing short of wishful thinking. There's no way you'll keep the case cool enough that the die won't damage itself at that kind of load.
That is unless the 1.5A spec is for a very brief, worst-case, transient load... and average current is really significantly less.