I'm using LTspice all the time for simulation and etc, but now I wanted to do autorouting (with some manual tweaking), I suppose LTspice cannot do such thing ? I want to make a PCB layout, how to do it in a simple way ?
I heard about many of those software, but which is most simple/easier to learn and process ? (I just tried EAGLE, and I have alot of things to learn such as making library, making schematic 'again' before board layout.)
Is there any simpler way to make board out of LTspice ? (Or I just have to surrender and make it slowly )
I heard about many of those software, but which is most simple/easier to learn and process ? (I just tried EAGLE, and I have alot of things to learn such as making library, making schematic 'again' before board layout.)
Is there any simpler way to make board out of LTspice ? (Or I just have to surrender and make it slowly )
Spice is simulation, any routing will be done in the PCB design package.
Forget autorouting, there is no such thing, there is interactive routing, but no autorouting.
The best way to lay out a board is concentrate on placeing, this should take between 60-40% of the time for a layout for analogue and digital with small devices.
The most important part of a CAD system set up is the libraries, these are critical and setting them up is a good way to learn the CAD system, as well as controlling your designs.
Forget autorouting, there is no such thing, there is interactive routing, but no autorouting.
The best way to lay out a board is concentrate on placeing, this should take between 60-40% of the time for a layout for analogue and digital with small devices.
The most important part of a CAD system set up is the libraries, these are critical and setting them up is a good way to learn the CAD system, as well as controlling your designs.
This is an important question - if one could netlist the schematic and read it into the PCB package you have eliminated an important source of errors and trhowing-away PCBs. It's almost impossible to manually transfer a schematic to a PCB unless it is small and very simple.
There are several low-cost or even free PCB packeges, but each has their advantages and disadvantages.
My suggestion: see which netlist formats LTspice supports, get the free/cheap PCB packages that can import one of those netlist formats, play with them and then select the PCB package you like best.
A separate issues is whether you wish to use manual or auto routing. I almost exclusively use manual routing - you can do so much better, and follow your own ideas, when doing that (unless you want to pay several kilodollars for a top autorouting package).
Most PCB packages have netlist-assisted manual routing. That means that all required connections are shown on the layout (the info comes from the netlist of course) as thin lines so you see what you have to route, and the line disappears when the route is done. Should you put down a wrong connection you'll get a warning.
You generally also can specify the minimum distance you want beteen tracks and tracks-pads and when during your layout you get too close you also get a warning.
Again, a great way to avoid errors!
jan didden
Even with the expensive packages there is no such thing as autorouting, it is an interactive process and even then most of the routing tends to be manual, apart from length matching, but you have to routes the traces so there is enough room for length matching. I use about £35Ks worth of software and add ons for PCB layout at work, and with the new digital packages and restrictions we use the auto-routing functions less and less, but do use othe automated routines that help speed up the layout process, such as auto BGA breakout routines. And manual routing will usually give the best results, based on component placement (the criticla skill in layout).
Most schematic packages will transfer info to spice simulation, as Janneman stated, using a schematic to layout is paramount for reducing errors, and it all starts with good libraries, get them right and everything else will follow.
Most schematic packages will transfer info to spice simulation, as Janneman stated, using a schematic to layout is paramount for reducing errors, and it all starts with good libraries, get them right and everything else will follow.
You can export a net list from LTspice (under the tools menu), but you will have no pin outs or footprints for your parts. You might take a look at this thread.
Best LTSpice to PCB
Best LTSpice to PCB
Forget about auto routing, there's only 1 good way to do it, manually. You can ofcourse add layout design rules, such as spacing, track with, PCB stackup, transmission lines, differential pairs, ...
PCB layouting is a real art, especially when designing high speed digital or sensitive analogue circuits. High speed in this context means "fast edges".
Professionally I use Altium, not as expensive as for example Cadance but still not cheap.
Whatever layout tool you use, start with finalising the schematic first, second is component placement, third are the most sensitive traces + any guard traces, 4th power / ground planes and last the remaining traces.
PCB layouting is a real art, especially when designing high speed digital or sensitive analogue circuits. High speed in this context means "fast edges".
Professionally I use Altium, not as expensive as for example Cadance but still not cheap.
Whatever layout tool you use, start with finalising the schematic first, second is component placement, third are the most sensitive traces + any guard traces, 4th power / ground planes and last the remaining traces.
yeah, I agree we can't rely on auto-routing, since there are many placement which has detrimental effect on the sound quality of an amplifier.
Well... what I mean is something like auto routing of wiring simple. (Previously I was drawing manually, and it takes me like many days to only design, then draw, and finally not suitable and redo. drawing using pencils really a headache regarding wirings.)
Well... what I mean is something like auto routing of wiring simple. (Previously I was drawing manually, and it takes me like many days to only design, then draw, and finally not suitable and redo. drawing using pencils really a headache regarding wirings.)
Very good advice. Marce is working at the opposite end of the spectrum to me wrt circuit complexity and density, but what he says holds regardless.
I've had access to and tried out a couple of CAD suites over the years, but now, working by myself, on the comparatively simple stuff I do (no motherboards, thank god!) I stick with LTSpice and FreePCB.
The 'project management' features of packages like Orcad drive me crazy (well, even crazier), but for big projects they're probably vital. Horses for courses and all that.
I've learnt, the slow way, by watching and taking notes as I go along just what these programs do. Where they put things, where they look for things. An important thing is your libraries. Your libraries. Of spice models, footprints and pinouts. I've put a deal of work into mine, but in return I know what's in them and more-or-less what's happening as I work. I store and use them carefully.
As with any computer program GIGO applies. Routing for me, in FreePCB consists of importing the netlist, with models that include correct pinouts and footprints - electrolytics and discrete transistors need checking. The outlines appear on screen, connected with ratsnest wiring, then I place the parts and route the tracks.
If you're doing stuff like amplifiers and you've been drawing layouts manually, do try FreePCB.
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Start off with a very simple circuit, eg a trivial r-c filter. You'll need to specify package footprints not in dimensions/hole spacing as you're probably used to if you've been hand drawing, but in terms of package names that contain that information. Most of what you need will be available in the FreePCB libraries, but if you need to create or edit one, that's quite do-able. You also need to associate this device information with the netlist you're importing, which can be done in various ways, see the tutorial and help file, they're not bad. Incidentally, if you work systematically, you can create netlists in a text editor if you really need to.
Keep looking inside files with wordpad or suchlike, a lot of them are readable text and you'll learn from that.
You will almost certainly find it frustrating at first, but well worth the effort if you stick with it.
Is there anyone here willing to turn a schematic (fairly simple done in Spice) into a PCB format for a noob like me? I have a fairly simple linestage design done up in Spice and was going to point to point the build...now I am thinking of having some PCBs made but have no idea how to create a PCB file from a schematic....honestly, i really wouldnt want to spend the time learning...i would rather pay someone if possible. Please shoot me an email if you are willing to assist....
Thanks,
Jeff
Thanks,
Jeff
I've only ever done layouts for pcbs I etch myself (long time since anyone else was daft enough to employ me for this stuff!), so mostly single-sided stuff. marce on the other hand, I think, lays out boards that are more complex than most medium size cities.....
If you're having someone else make them for you, it might be a good idea to get them to tell you what they like to work from.
Also, show us yer schematic!
If you're having someone else make them for you, it might be a good idea to get them to tell you what they like to work from.
Also, show us yer schematic!
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