Let me start with your last question, I would highly recommend NOT soldering components on both sides unless you have a really good reason to. I have made a few boards with double sided soldering and it became more of a pain then anything.
As for the routing itself, my answer here might help you out some, but I will elaborate some for your specific circumstances.
Part density can become an issue when you are hand soldering, but it is difficult to give exact numbers as everyone will be different with how comfortable they will be soldering and what parts it is. As a minimum you will probably need 2 soldering iron tips width apart. This will give you the room to get the iron in to work on one part while not hitting the other. You might also want to take into account the angle that you like holding your soldering iron at as you won't want to be resting your iron on another IC. If you have a shakier hand then you might want to see how much your hand shakes and space your parts at least as far as the tip of the iron moves as you are shaking.
I would also avoid running traces between legs of SMD components. A lot of people will do it just because it passes DRC, but if you are hand soldering with no soldermask, it becomes very easy to accidentally bridge to the trace.
It is also helpful, but not required, to bring your traces out straight from any ICs and then after a little room branch them to the direction they need to go. This will help you line up your IC properly as well as to be able to get the solder in place easily.
And finally, going from through hole to SMD, you will find that many of the tricks that you can use with through hole just wont work with SMD. Things like having no vias because you are using a through whole component to jump to the back side, instead you might have to go back to your schematic and change things around to limit the number of vias used. Also you can usually run traces under through hole items, but this may complicate things more with surface mount.
Overall, just practice and you will pick up tricks just like I am sure you have picked up tricks with through hole.
A very nicely presented 1st question (or 100th or ...).
Lots of detail to assimilate but it all seems relevant and useful if a good answer is to be found. I cannot spend the time needed now on this but will throw in a few comments and see what others have said later.
I spent about 15 minutes just going to and fro over the circuits and layouts and doing some basic sanity checking. I'm sure your rule checking would have eliminated basic errors.
I have NOT tried to work out what your fault may be caused by specifically - and suspect that it may be a hard fault or misthought rather than the design areas touched on below. BUT any of the following may relate.
Have you tried placing the whole PCB on a PCB ground plane? Can help heaps with single sided. May not.
The two unrouted nets shown presumably have wire links added by hand. (If not that would be an easy fix :-) )
A single side board MAY be doable but with such a complex beast with two switchers and the ability for feedback between them you'd need real care, a scope glued to your right hand and some luck. Even a double sided board (which is about as cheap and quick from many board houses) costs much the same.
A problem is (which may have led to a problem that you get) that the IC seems to have pinouts which assume you can route across the IC with ease so that critical current loops have little area. Because you are on 1 layer this is not true and you have several such loops that more or less overlap and seem to invite disaster.
The obvious ones to minimise to start are the two inductor loops p7-L1-p15 and p16&p17-L2-p14.The L1 loop involves an added jumper and how you route this may have an effect.
Noise getting into the feedback dividers can be bad news indeed. I see you have used c5 across R4 as per their circuit but have no cap across R8 - shown as Copt on one of their circuits and not on another. Simplistically this passes fast load transients or noise that affects output into the feedback pin at a greater rate and level than you get from the divider. Presence or absence in SOME designs is life or death.
Draw lines on printouts of the layout with different coloured markers as to where the loops seem likely to be that are used by different processes (Inductor currents, feedback dividers, ...). (Draw on a screen if that works for you - I find paper and markers more powerful). You can then see likely interactions and any loops that have large open front doors for noise / cross coupling to rush in and out of.
More later maybe.
Best Answer
High voltage PCB design
High Voltage PCB design for arc prevention
A few reasons why:
A quick look at some creepage/clearance tables :
clearance table III
creepage table IV
seems to confirm that
creepage distance
>clearance distance
, especially with higher pollution degrees.Pollution degree is a measure of how the environment could affect your PCB. See: Design for Dust.
Description of various polution degrees (table 1):