Designing power supply with 5v and 3.3v from a 12v supply with switching regulators

Question

I have 12V DC coming in from a power brick and I need to supply 5V @ 1A for USB and 3.3V @ 5A max for mSata and PCIe. I basically need to make a small atx power supply that I can integrate on my custom board and I don't need every supply that comes with a full ATX, just 3.3V, 5V, and 12V. I would like to avoid using a linear regulator because of heat. I also need the chips to be large enough that I can prototype a circuit on a breadboard. I like the TO-220 package size that most of the linear regulators use. What regulator family should I be looking into? I have looked at a few different types but I was overwhelmed by all of the choices.

I designed a power supply using the TI power architect tool which used some very small chips and I had a board made based on that. When it came time to assemble (chip I do by hand), the chips are very tiny and it is impossible to debug. Needless to say, the board does not work. I have tried reworking it a few times, but no luck. The chips I used were:
http://www.ti.com/product/tps40305
http://www.ti.com/product/tps40304

I'd like to start all over and make a proper working prototype on the bench before making another board.

Answer 1

I'd like to start all over and make a proper working prototype on the bench before making another board.

A better idea might be to resolve the issues you have with the TI devices/PCB. What you might find is that your assumptions about power layout on that PCB were incorrect but you'll never realize that if you move on to a different design and you'll quite possibly carry that erroneous thinking thru and find your self in exactly the same situation.

As for a proper working prototype on the bench - it's unlikely that anything other than a decently designed PCB will suffice and you will be left scratching your head once more.

I'm 56 and I use glasses and magnifying goggles to help me to solder 0603 components and SMT chips so you should consider that this sort of equipment comes with the territory of the technology.

You might find some non-SMD parts that are easier to breadboard but also you might find that these don't perform adequately if you don't use a circuit board designed to make this circuit work.