We’ve often heard you should do everything twice. The first time is to learn what you need to do, and the second time is to do it right. We bet [Ian Carey] would agree after taking his old linear power supply PCB and changing it to a switching regulator design. You can see more about the project in the video below.
The first power-up revealed a problem with the 3.3V output. We’ve often thought it is harder to troubleshoot a new design than it is to repair something that is known to have worked at one time.
The problem was a misread of the datasheet, something we’ve all done at least once. Luckily, a few component value changes cleared things up. It probably would have been feasible to repair the original boards, but it was cheap enough that he just had new boards made.
We always enjoy seeing the thought process behind a project. We also appreciate seeing the bad with the good. It is too easy to just skip to the working version and not mention the steps it took to get there, but that’s where you tend to learn the most.
The video mentions how PCB layout for switchers can be a big deal, and we agree. We are always fans of switching regulator designs made to plug into linear regulator PCB footprints.
Cheap enough maybe, but so wasteful…
what is wasteful?
Why is it “so wasteful?” How is it “so wasteful?” What suggestions would you offer to improve the design?
Constructive criticism(s), please.
Well, instead of having a whole new batch of boards made, I’d have replaced that single resistor with a correct one. Throwing away functioning boards because of a single resistor with the wrong resistance value could be considered wasteful by parts of the audience.
Not everyone has a hot-air rework station. Offering the first run as a dual, independent 5VDC supply to anyone willing to cover shipping would have worked.
Although, If I were designing it, I’d try to make it more narrow so it’s easier to connect to the side pins when in a breadboard. As is, there’s barely room to squeeze a single wire in next to the FR4 on each side.
It doesn’t take a hot-air rework station to remove and replace a simple SMD resistor.
A normal soldering iron is all it takes.