First time designer looking for feedback


#1

Hi guys,

I’ve been designing this board for a while now, and I’ve got to the point now where I personally am confident that it’s ready to be sent away to be prototyped. Since this is a one off for me though, it’s not being produced or anything, and I honestly have never designed a board before, could I ask the favour of a couple of people quickly looking over the project to make sure it all makes sense?
A quick note on track widths: The MOSFETs are switching up to 2A, and everything else is up to 800mA.

Cheers folks!


#2

I’d make the connector pads larger.
And check the regulator datasheet for input & output capacitor requirements.


#3

Which connector pads are you referring to? Just the MOSFET pads, or all of them? And I’ll check the data sheet later when i get the chance. Cheers though!


#4

I was talking about the screw connector pads.
But it wouldn’t hurt to make the FET pads larger.
I usually use oval pads as wide as possible for the pin spacing.
For the pcb fabricator etching, it’s best o have as much copper as you can fit in (less copper to etch = faster etch = less problems).
So I always use a ground fill on both sides of the pcb.


#5

OK, I’ll get that changed when i get home tonight.When you start talking about the etching, I’m afraid you’ve lost me - my plan is to send the design to Dirty PCBs for prototyping, and let them do the work. Obviously, if my PCB design isn’t quite ready for manufacture, then it needs work - what exactly needs done though, because I’m afraid I’m lost from that point on!
Cheers


#6

It was a general remark, I think. It is a good habit (I personall tend to, as well). But then it is more of an issue in boards below 6mil/6mil (trackwidth/spacing). In your case that should not be a concern. Go ahead an let them do their thing.

IMHO, at certain point, however, it is good to have basic knowledge about PCB manufacturing to put things in perspective.If you are interested in infos there is plenty of stuff about PCB manufacturing process in the www. Maybe you want to watch one of the many videso that hang around in Youtube covering the issue. There’s a lot of decent stuff in various channels.


#7

You might find it interesting (and instructive) to have a look at what happens to your design files after you send them off for production. Eurocircuits have produced a nice series of videos on the whole process. I agree with @straubm that understanding the process will help in you to get things in perspective.

http://www.eurocircuits.com/who-are-we-and-why-have-we-made-this-film/


#8

… but don’t mistake Eurocircuits to have anything to do with cheap PCBs :slight_smile:


#9

OK, thank heavens… My brain is temporarily frazzled, so i didn’t think i could take much more in :slight_smile: I’ll increase the pad size when i get home, then send them away.
Thanks for all the help!


#10

Well, bang goes my evening :wink: better than playing pc games i suppose… I’ll work my way through them for sure!

Daniel


#11

Zeners on the mosfet drains would protect against inductive loads like points solenoids


#12

Zeners? I’m afraid i have no idea what they are… I’ve used simple diodes across the motors as protection, assuming that would do…


#13

Zener diodes are special diodes, which are manufactured/binned for reverse thresholds and are rated for currents in the ‘blocking direction’ (if the threshold is reached and overcome).
A special type of those are transient voltage suppression diodes.


#14

I presume a normal diode wired across the motor would suffice though? The motor is wired through a Capacitor Discharge Unit which is supplied with up to a 2A AC supply, and only supplies an instantaneous current. This is what i based my design off:


#15

… and you are good to go.