The "oblong" pads work well esp for hand soldering.
It's also an idea to use a squared off pad for pin 1 identification (in general)
Makes it easy to avoid "Oops I forgot the pcb had been turned over !" issues. Unless that's just me
Critique my PCB layout
- Thread starter jasonallenh
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The "oblong" pads work well esp for hand soldering.
It's also an idea to use a squared off pad for pin 1 identification (in general)
Makes it easy to avoid "Oops I forgot the pcb had been turned over !" issues. Unless that's just me
Matador
Well-known member
For connectors agreed it isn't a problem.
For me, I go through 3 phases: when a board is new, I like to use screw terminals for all connections, so I can install and remove the board in a chassis easily for tweaking. Second, I'll solder directly to the pad for a 'semi-permanent' installation, if I need to do testing in a near 'final' form. Lastly, I'll wire to the through hole for a permanent (but still repairable) connection.
2.54mm for permanent wiring is where I find the most difficulty, especially if there are 5 or more wires right next to each other, and no terminal is used. 3.5mm is much easier to permanent wire (at least for me), due. to the increased spacing between the wires, and also the pads can be bigger meaning easier to tin and more surface area for the wire to stick, and (hopefully) less chance of the pad delaminating.
But still agreed: if you only ever plan to use connecters and not wires then regular 2.54mm pitch is just fine.
Agree wrt soldered in wires. I've had loads of trouble myself with wire to board soldered connection with a tight spacing.
I that particular case - wires 'bunched up' inside a sensor assembly , PVC insulation shrinking back, PVC insulation chafing and shorting to metalwork.
Not very nice !
jasonallenh
Well-known member
I updated the layout with (hopefully) better routing choices based on some of the comments here, added decoupling, and bumped trace width up to 30mil. I put a couple 0603 bypass caps on the underside of the PCB. Like before, the remaining rats nest lines are just the remaining ground net and will be connected once I do the pour for the ground plane. All the silkscreen adjustments and pad size adjustments still need to be done, but I'd like to address any more major routing issues first. Let me know what you think!
I can see some connections on the bottom layer that could easily become the top (component) layer. To give a better 0V copper pour on the bottom layer.
Philbo King
Well-known member
- Joined
- Aug 15, 2023
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The LL1517 -- 'shown from bottom' view? (Pin 1 looks wonky, disregard this if it's the transformer; they often have wonky pinouts).
U2 looks ok if this is a component-side view.
jasonallenh
Well-known member
It's shown from top view. I had to build a footprint myself, but that's a little more straightforward when the datasheet tells you exactly what you need. I did print it out to make sure it lined up as expected.
jasonallenh
Well-known member
SO at about 1am, I burned everything down and started over. This version is much more symmetrical. I think this is my final answer! Almost nothing on the bottom layer, traces at 20mil minimum, pad sizes more appropriate for hand soldering (though admittedly still a bit on the small side- fine with me though) teardropped and oval pads on the connectors. heavier traces on the transformer just because of the vague thought that I may need mechanical strength, and the silkscreen is cleaned up (though the text may actually be too small... might adjust once I see how it looks after printing). Thanks for your help, everyone- This has been a massive improvement. I'm going to not look at it for a couple days and make some final adjustments.
MidnightArrakis
Well-known member
Here's my worthless 2-cents worth of assistance:
1) Move the "IN" and "PSU" connectors in a bit so their pad-hole centerlines fall onto the 3rd grid-line (0.100" grid is shown???).
2) Then route the track from C16+ towards the left-edge, down a bit, over to the right and under CP1 and then reconnect it back to the bottom of R20. Because.....
3) This will then allow you to route the net from U2-Pin5 over to the bottom of C19 on the TOP (RED) side of your PCB!!! YAY!!!
4) You -- could -- move R19 over to the left just a hair to create some room between it and R20, so the route going to CP1+ from U2-Pin8 could "sneak" between them and then you could run a TOPSIDE route from the bottom of R19 over to CP2+. YAY!!! AGAIN!!!
5) From there.....I would then take the BOTTOMSIDE (BLUE) route that goes from >> T1-Pin1 << (you are identifying it as "U1", but transformers use the REF DES of "T" and > NOT < "U"!!! "U" is used for IC's!!!) to the top of R15 and instead route it up to the pad of C14+. This is because, as you have it routed now, the capacitor C14 is on "stub-routes". When I was designing PCB's for a military-related communications equipment company involved with designing and building all manner of "covert and secret intelligence-gathering, surveillance and tracking-operations" equipment for U.S. agencies "that don't exist".....the "RF Engineers" > HAMMERED < into me that in order for circuit capacitors to effectively and properly "do their thing", that >> YOU SHOULD ALWAYS TAKE YOUR ROUTES TO A CAPACITOR FIRST << before going to any other component!!! While I am more than certain that there are members on this forum who will highly disagree with me about this, all I can say is, is that all of the equipment that this company had designed and built for all of these "covert" U.S. agencies all worked EXCEPTIONALLY WELL!!!
In other words.....the route going from -- T1-Pin1 -- over to C14 will work "well enough" as you have it routed now.....but, C14 will "perform better" if the route from -- T1-Pin1 -- was routed up to C14+ first. Should you look at and analyze for a moment the difference between such a small change in the routing, then you should be able to figure out why my suggestion makes sense!!! CHECK IT OUT!!!
And then, if you carry that thought over to a PCB that has over 1,500 components on it and you route all of the capacitors in the manner as I have just suggested, the entire circuit.....remarkably.....performs much better than you could have ever imagined!!! BIG YAY!!!
6) Which means.....that probably C18 should be placed -- BEFORE -- U2 and then routed to U2-Pin1 and Pin2. Just a thought.....
7) Similarly.....The connection from -- T1-Pin3 -- would be good going to C17 first and then branching off to the connections over to U2-Pin7 and R22. As you can (hopefully) see.....the route would be coming from the transformer, to the capacitor FIRST so it can effectively "do its thing" and then over to the rest of the components. It's a small change, but it can have a BIG effect.
8) I'm assuming that the pin "CR" on the PSU connector is your power-supply "common" net, that also connects over to the top of the "IN" connector, which is also routed over to C15, you can actually delete the "C15" route.....because once you pour your "Copper Pour" ground-plane, C15 will (should) connect to the "Copper Pour" anyway. Just make sure that you have your pad thermal-reliefs setup correctly. While I like to use 20-mil "spokes" for my thermal-reliefs and I even frequently use 25-mil reliefs if I can, there are others who think it's nothing to use 15-mil or ever 10-mil spokes. NOT ME!!! "Hefty" is good!!!
9) You may wish to move the "U2" silkscreen from under R15 and instead place it over by U2-Pin1. If you were a "PCB Designer" for a fairly good-sized company, they usually like to have the REF DES silkscreens placed by the components' "Pin-1".
10) Similarly, the -- + -- sign of electrolytic capacitors is usually duplicated and placed -- OUTSIDE -- of the component silkscreen. Silkscreen REF DES's are normally difficult, if not impossible, to see when they are underneath the body of a component!!! Naturally, if the component REF DES silkscreen is placed -- OUTSIDE -- of the component outline silkscreen, then.....DARN!!!.....you can easily see it and know which component it is associated with!!! It's amazing with how that all works out, isn't it???
There are some other items I see that I could mention, but I need to go get myself some dinner now.
And, remember.....I am just a "beginner" at designing PCB's!!! So.....what do I know???
>> TOPSIDE -- 10-Layer PCB using 5-mil "track and space":
>> BACKSIDE
>> TOPSIDE -- 10-Layer PCB using 5-mil "track and space":
>> BACKSIDE
GOOD LUCK!!!
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@MidnightArrakis Whatever the reality of your Covert / Military experience - I suggest you "give it a rest" since
A. Would you really make that so known on a public internet forum ?
B. Even if so - this isn't LinkedIn
I daresay many of us have experience and skills of note yet don't feel the need to reference them at any and every opportunity.
A. Would you really make that so known on a public internet forum ?
B. Even if so - this isn't LinkedIn
I daresay many of us have experience and skills of note yet don't feel the need to reference them at any and every opportunity.jasonallenh
Well-known member
@Newmarket I am fairly certain our intelligence friend is just here to intimidate me due to my anarchist tendencies 
MidnightArrakis
Well-known member
[A. Would you really make that so known on a public internet forum ?] -- What does it matter??? My design work within that area took place between 10-to-30 years ago. I hardly doubt that Chinese or Russian spies are going to track me down and force me to eat spinach in order to learn of the type of PCB's that I used to design. Technology has advanced WAY BEYOND what I was involved with designing back then these days!!! We used to create vias with -- NO COPPER -- within the barrels and instead place 0603 capacitors and resistors within those vias as a way to not only connect the TOP and BOTTOM layers together, but also to save space on the PCB so we could pack the PCB's more densely.@MidnightArrakis Whatever the reality of your Covert / Military experience - I suggest you "give it a rest" since
A. Would you really make that so known on a public internet forum ?
B. Even if so - this isn't LinkedIn
[B. I daresay many of us have experience and skills of note yet don't feel the need to reference them] -- YES!!! I am certainly well aware of the experience and skills of many of the members on this forum!!! I had only made the mention of my working on "covert" PCB's just to give the OP a reference to my background so they may be able to give some credence to what I was suggesting. I simply felt that somebody (i.e., "me") just randomly jumping into this thread and providing the detailed extent of explanations as I have, they just might want to know a bit of a person's background as to -- why -- they were suggesting what they were suggesting. As usual, as I am finding out.....there are so many of those who come from the current "Cancel Culture" and become so easily offended by what someone has posted here on this forum!!!
> JasonAllenH -- [I am fairly certain our intelligence friend is just here to intimidate me due to my anarchist tendencies] -- Well.....well.....well...............I am sorry to read that that is how you feel about all of my detailed suggestions I had provided to you earlier!!! Because I take it that your comment posting to me is kind of like a "punch to my gut" for only trying to help you out with your PCB layout, I have now decided it is best that I >> NOT << provide you with a URL link to an online folder that I have which contains well over 450MB of -- PCB Design Guidelines, Standards and Techniques -- which would have provided you with an extensive and detailed amount of PCB-design layout information that would have answered -- EACH AND EVERY QUESTION -- you would ever have on how to properly design and layout any manner and/or type of PCB imaginable!!! So.....GO **** YOURSELF!!!
I spent the time to go into a fair amount of detail to help and show you how to improve your nearly finished PCB-layout and then you show me your "appreciation" by punching me in the gut!!! THANKS!!!
My detailed explanations weren't here to say "how 'GREAT' I am" or any other inferred inference. In order for a PCB Designer to -- see -- how rats-nets can be successfully routed on a PCB takes experience, which then takes time. I offered you suggestions that were -- right in front of you, but - YOU - couldn't "see" them -- because you don't have -- that -- skill yet. But, by taking my suggestions to heart and implementing them, you then would have (hopefully) learned something that you could use on your next PCB-layout project.
As of right now.....you can count on >> ME << to -- NEVER -- offer you any further assistance on any of your future PCB-designs!!! And.....my 450MB+ of "PCB Design Layout Guidelines, Standards & Techniques" would have leapt you from being a "PCB Kindergartener" to a "PCB Designer" in a rather short amount of time..... assuming that you would have studied all of the material that is contained within my online folder. It -- IS -- extremely exhaustive and extensive!!! And, all of this information is from the many industry major players in "PCB Fabrication & Assembly" and contains highly-detailed information on -- HOW -- to design a good PCB, as well as -- WHAT -- to avoid that can cause fabrication and manufacturing issues. But, I am guessing now that you are already knowledgeable about all of this, right???
By the way.....I would be interested in seeing how you would layout and route an 8-layer PCB that is only 1.25-inches square, has 210 components consisting mostly of 0201 parts, a 256-pin micro-BGA, a handful of 64-pin micro-PLCC's, an 8-Pin DIP that contains its own micro-miniature microphone and the PCB is routed using 4-mil tracks-and-spaces with 4-layers dedicated to "Split Power & Grounds"!!! Tell me how you would layout and route a PCB like this. I'd like to know!!!
In conclusion.....I now strongly suggest that you completely ignore -- EVERYTHING -- I suggested and wrote about concerning your PCB-layout and that you just go ahead and do whatever you want to do!!! Your PCB-layout apparently doesn't need ANY of my suggestions, as it is already nearly perfect as it is!!! GO FOR IT!!!
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Oh Dear. It seems that someone doesn't read / understand emoticons
jasonallenh
Well-known member
......Hey man it was just a joke.... I am happy that you provided input, and I'm sure it's good input. I think it's perhaps the method of presentation that might have been a little off-putting? none of this is that serious. Have a good weekend
Tough Crowd 
MidnightArrakis
Well-known member
PFFFFFTTTT!!!
[perhaps the method of presentation that might have been a little off-putting?] -- Unless I am missing something here.....my numerical points of presentation were merely and purely technical in their nature, with only just a hint of "happy humor" when I included a "YAY"!!! Nothing else was inferred.
There are some other areas of improvement that I could relate to you about your layout, but you can obtain your feedback from the others on here, because my input to you doesn't seem to be all that well appreciated.
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amplexus
Well-known member
Reading comprehension is really lost on some people I guess. And doubling down after the misunderstanding was corrected too. Seems about right.
Oh Dear. It seems that someone doesn't read / understand emoticons
I don't have to read all your words, and don't plan to, to opine that you are breaking rules.
Consider this your warning.
JR
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