First of all, calling a 3BB raise with PP depends on the remaining stack on the player - if he has 17BBs left its not worth it, if he has 97 it surely is and so on.Additionally, every particular villain is to be treated separately.
The same goes with your stack. I suppose you play fullstacked,and 5-6 BB's on unopened pot is just too much, as you will only get called with hands better than yours, or everyone else will fold.Actually, the implied odds the opponents get against you depends on your reactions also, i dont believe you will risk all your stack with just TPTK or overpair? So In this case, even if they flop a set, they wont be able to win your entire stack, as you will be protecting it, or have a better hand. Thus, the implied odds they get against you are smaller, you dont need to raise more.3,5 times the bb is just about enough.
Implied odds is a lot more complicated than pot odds, it relies not only on raise/stack size and the texture of the board, but on psychology and opponent's behavior(yours in the second case).