Hi All,
Apologies for this idiot question. I am at the steep end of the learning curve.
I have been building some simple solid state amplifier circuit. So far point to point build and simple simulations in LTSpice. I would like to get to the point where I can transfer this to a circuit board so as to make a more reliable and consistent cleaner result.
Is there an easy / good way to do this?
Is there some software package that will give me a layout based upon an LTSPice file - or are there people here that like doing layouts and can provide a fellow hobbyist with something I can get made by a custom pcb place like OSH Park?
many thanks
BeardyWan
Apologies for this idiot question. I am at the steep end of the learning curve.
I have been building some simple solid state amplifier circuit. So far point to point build and simple simulations in LTSpice. I would like to get to the point where I can transfer this to a circuit board so as to make a more reliable and consistent cleaner result.
Is there an easy / good way to do this?
Is there some software package that will give me a layout based upon an LTSPice file - or are there people here that like doing layouts and can provide a fellow hobbyist with something I can get made by a custom pcb place like OSH Park?
many thanks
BeardyWan
I'm not sure of any that can directly use an LTSpice schematic (but there probably are). I used KiKad, which is pretty powerful, free, but does take a while to get the hang of.
There are plenty of pcb manufacturers around that will do proto runs for not much money. I think I used itead, I've seen pcbway advertised here as well.
Tony.
There are plenty of pcb manufacturers around that will do proto runs for not much money. I think I used itead, I've seen pcbway advertised here as well.
Tony.
Eagle is compatible with LTSpice file format I think. It is free for hobby use, with the limit on PCB size.
Have spent the afternoon playing with Eagle and easypcb
Eagle doesn't accept an import from LtSpice. Sinc they developed their own Spice simulation they dropped support of this import function. - So draw it all over again.
Eagle seems a bit painful so I looked at easypcb. This will take a netlist import and so you can pull files from LtSpice, BUT you have to edit the .net file and assign package information to every component prior to importing and the libraries on easypcb aren't exactly self explanatory. I spent some time looking at component datasheets for bits I have purchased to build point to point, and nowhere could I find package information that correlated with possible component footprints that were available in the library.
At this point its back to point to point.
Eagle doesn't accept an import from LtSpice. Sinc they developed their own Spice simulation they dropped support of this import function. - So draw it all over again.
Eagle seems a bit painful so I looked at easypcb. This will take a netlist import and so you can pull files from LtSpice, BUT you have to edit the .net file and assign package information to every component prior to importing and the libraries on easypcb aren't exactly self explanatory. I spent some time looking at component datasheets for bits I have purchased to build point to point, and nowhere could I find package information that correlated with possible component footprints that were available in the library.
At this point its back to point to point.
The simulation schematic is often quite a bit difficult than the circuit schematic - at least if you start to include the layout/component parasitics. It would be nice with a simulation schematic import, but I'm not aware of any schematic tool that does that - at least not one that I can afford. I just redraw the schematic in the schematic portion of the CAD software, generate a netlist, and start the layout.
If you're looking for a fully automated sim schematic -> layout, I think you'll be disappointed. There's a lot more to layout than just connecting the dots. Many CAD packages offer auto-place and auto-route. They can work for routing digital busses, but are mostly useless for anything analog.
Tom
If you're looking for a fully automated sim schematic -> layout, I think you'll be disappointed. There's a lot more to layout than just connecting the dots. Many CAD packages offer auto-place and auto-route. They can work for routing digital busses, but are mostly useless for anything analog.
Tom
It's not just parasitics. A simulation schematic almost never includes connectors, or connections to off-board components, which are necessary in all but trivial fabrication schematics. Simulation often concentrates on small sections of a schematic rather than the whole circuit that appears on a PCB. If you are serious about simulation, you will use it to investigate things like tolerance build-ups, the behavior when devices are at the edges of their specification limits, and thermal effects. Sometimes this means adding (or removing) components to the simulation, to model some factor not otherwise represented.
In short, simulation and fabrication are two different activities, typically requiring different kinds of information to be saved in their respective schematic files. Yes, it's annoying to enter a schematic once in LTSpice, and again in KiCAD. KiCAD recently incorporated support for "ngspice" as a built-in simulator. I haven't tried to use the feature, but from the chatter on the KiCAD User's Forum ( KiCad.info Forums ) it appears to be awkward to do simulations, and the simulations shown as examples have been very basic, simple, circuits.
Dale
PCB layout is a task that can take significant effort to master but you can often achieve usable results with a modest investment of time and effort. Keep in mind that you are not only picking up knowledge about the physics of circuit layout, but also about the PCB industry, and how to operate the tools you have selected. The folks over at the KiCAD User's Forum have walked totally inexperienced folks through the process on several occasions; I suspect that other tools have a similar support group. If your designs are similar to other, previously published, projects you may already have an example to guide your efforts. And, if you want to frighten yourself with all of the details that must be considered, the people at Seeed Studio have published a 40-page handbook that covers the current recommended practices in the industry (see http://statics3.seeedstudio.com/fusion/ebook/PCB%20DFM%20V1.1.pdf ).
The marketplace for fabrication of quick-turn prototype PCB's is rather crowded and appears to be somewhat cut-throat. Everybody always has some gimmicky "special offer" going on. It pays to shop around a bit, but read the conditions carefully.
In general, the longer you can wait, the less you will pay. (My employer recently bought a batch of 50 boards, delivered in 30 days, for the same price as 5 boards with a 10-day turnaround.)
You may pay more for packing and postage than for the boards themselves. Air transport can have your boards on your workbench within a few days after the silkscreen has cured - for a price - but surface mail takes weeks (and in a few cases may never arrive).
Minimum order quantities are typically 10 boards, though some vendors may offer 5 or even 1, but the per-board cost is higher.
Most vendors will run your board design through some kind of "error check" before they accept your order. This ONLY verifies that the board is manufacturable to their standards, and will not uncover dumb mistakes that you have made. GIGO.
OSH Park seems to have a good reputation for their product and service, but there are others who can perform as well. Over the last 15 years or so I have purchased several dozen different boards from at least half a dozen different suppliers. Every one met their advertised specifications, though some had more margin than others. I never had a "bad board" that was the fault of the board house, though all of my boards were fairly run-of-the-mill, routine, board designs.
Dale
The bonus for BeardyWan and myself (among others on DIYAudio), is that I could, theoretically, go pick up my boards from OSH Park on a bicycle. 🙂
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