I’m a beginner in PCB design, and I just wanted to know whether can I make a single layer PCB with only SMD components on top layer with traces also in top layer.
Thanks in advance!
Sure, just fill the bottom with copper and make a ground plane out of it. That will prevent you from routing any traces on it. 2 layer boards are just as cheap as 1 layer. Or if it’s really a 1 layer fab, then don’t send them the B.Cu.
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Why would this be useful:
As long as you don’t place any via’s on your SMD PCB all tracks will stay on the same copper layer.
Doing everything on one layer is quite limiting. You don’t have many routing options, and probably want to add wire bridges in some locations. For this I recommend to use the bottom layer and via’s. You set the design rules to a big via with corresponding hole diameter, and then use it to solder the bridge wires in. The copper tracks you then lay on the other layer is then good documentation for where to solder the bridge wires.
[Edit] In addition to this, why limit yourself to one layer? A GND plane is the single most important extension to a single layer PCB, and you can buy PCB’s with copper on both sides for (almost?) the same price as single layer PCB’s. Same technique applies: In Pcbnew you use a via for each GND connection, and on the actual PCB you make, you solder a short piece of wire through it (There are also bushes specially made for this).
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yes you can.
On a simple board you probably can make all the connections on one side. Give it a try. The cost of a PCB is the same 1 layer or 2 layer.
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Yes ! I am doing this all the time (though often combined with THTs).
The proposals given here are useful - but you might as well simply route on one layer and nothing else.
Its true that costs are the same for a commercial 2-Layer PCB. I only use the single layer version because I am manufacturing my own PCBs using home equipment.
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I also do mainly single-sided PCBs. The reason is that the PCBs go in (pre-existing) steel or aluminium enclosures without further insulation. And I don’t trust the soldermask to provide sufficient insulation, so vias and traces on the bottom layer might create shorts.
Although the boards are simple, they contain quite a few 0R bridges to allow routing. 0Rs are cheaper than a four-layer board.
Just wanted to add another reason why one chooses a single layer board.
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I suspected as I began reading your question that you
might be making your own board. Good luck.
It’s a great feeling of accomplishment when it is all done. Especially when you have software that can make such great art.
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@wxE5 makes a great point, soldermask is not a useful insulator so if your board must mount flush to a conductor (instead of on standoffs or with some thin insulator between), it should not have any copper on the back layer.
Single-layer is also the norm for metal-core PCBs, as are widely used for any design involving high-power LEDs for example. You can get multi-layer metal PCBs but they are expensive and I haven’t seen too many.
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There are benefits to having the bottom layer as fully flooded copper while still going for a single-layer design - thermal expansion.
if the TOP is SMD (and no via’s as previously mentioned) and the BOTTOM is fully etched away, depending on what type of heating that the PCB could experience, it could bow the card…
I have been working with IMS for some time and I am expanding into metal-clad ceramic to improve the thermal conductivity and in this instance I want a dual-sided ceramic but more for thermal matching
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There is nothing to stop you having a flooded or hatched bottom layer that is unconnected. Then if it contacts the support, no problem
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Exactly, I am designing a ceramic based PCB at the moment and the bottom will be contiguous copper to mitigate a mismatch in thermal expansion.
With an AlN core, this is a DBC process so you don’t get it for “free” as you would with a double sided core
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