okay, makes sense.
Each regulator may not draw full power both at same time, in fact it is VERY unlikely I will even pull close to half of the rated values I stated. I haven't yet calculated it. I just calculated up everything as if it had all turned on (which is impossible, as for example, only one LED is on while the other is switched off, and vice versa).
So, I should get a switching regulator that can handle about 4A (to be on the safe side), then get a low drop out voltage regulator that only has a drop-out of like 0.3-0.4 volts so it can produce the 5 volts from the 5.4 volts the switching regulator will put out?
Now, these will be on the PCB, the walwart (12 volt wall plug) gets plugged into the wall, then via a barrel connector on the PCB board, it connects to the PCB supplying power to the switching regulator, then to the circuit and the LDO regulator.
SO, just reading up on all these buck converters, it looks like the majority of them don't even use Tantalums. It seems almost all of them are asking for the Ceramic Caps.
Heh, I was just looking at that Diodes AP65403SP one. .86 per 100 from Mouser. that's under a buck! (lol, get it, a buck?!)
And yes, been reading about that frequency stuff. The Vishay Data sheets are very informative on it and explains where each of the components should go...I think if I use those same methods and apply to the Diodes chip..I should be okay...however, this is not a 4-layer board, it's only a 2-layer.
http://www.mouser.com/ds/2/427/sip12116-364719.pdf <--- Page 12