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#general
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# general
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Jorge Marin

11/12/2021, 7:18 PM
hello all, I have a very basic question: is there anyone doing full analog designs in open-galaxy (the cloud platform from efabless)? I don't have access for the moment to my own linux server account, so it would be helpful to have access to all the installed analog tools. If so, can anyone give some hints about how to get started with this?
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Luis Henrique Rodovalho

11/12/2021, 7:21 PM
Xschem, magic and ngspice are already installed in efabless opengalaxy. The Sky130 PDK is also there. You just need to open the terminal and run xschem.
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Jorge Marin

11/12/2021, 7:50 PM
thanks for the reply, Luis! OK, so I can trust that the analog flow realized by the tools installed in opengalaxy are trustable to have a design that can be fabricated, right?
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Luis Henrique Rodovalho

11/12/2021, 7:55 PM
The analog flow isn't really complete right now. You can make your schematics with Xschem, simulate with Ngspice and make the layouts with Magic. Magic also extracts the layout netlist and checks DRC. LVS is run with a python script from Open PDKs. I know you can run each one of these tools alone. The problem right now is to generate layouts from schematic. It's not as straightforward as with commercial tools.
I make my layouts from zero and extract the netlists from them, avoiding schematics and LVS entirely. It far from practical, but one can make simple designs this way, as amplifiers and oscillators. Mixed signal and RF projects are really hard to make. The digital flow is very far ahead of the analog flow right now.

https://www.youtube.com/watch?v=bm3l21ExLOY

Try those tutorials. They are a good introduction and are also free.
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Jorge Marin

11/12/2021, 9:40 PM
great info, thanks Luis! do you know if there are any initiatives to improve the analog flow in the community? I would be interested in understanding how could it be improved - from what you mention, it probably involves upgrading the PDK to have layout cells generated by the schematic netlist by the way, are you using open-galaxy or you installed the flow locally?
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Luis Henrique Rodovalho

11/13/2021, 1:24 PM
I make all my designs locally. I've tried open galaxy only once and it's not worthy it, because the main advantage of the open source tools is that I can do everything offline, without connecting to a license server. The biggest problem with the analog flow is standardization. It is not easy to just clone a github project and run all simulations. This way, it's very hard to reuse designs. It's hard to make a basic block from scratch with the tools, but it's not that hard to route everything at a top level. Commercial tools, as Cadence Virtuoso, have libraries and cellviews. It should be easy to import a library with the desired block and reuse it, as everyone uses the same open source PDK, but it isn't, even if everybody uses the same software with the same versions. The closest thing we have for standardization is Open PDKs, and efabless open galaxy doesn't even use the same standard path for the PDK libraries, as far as I remember. So, almost every design has testbenches with different library paths. You can't just add them to open galaxy and run everything.
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Jared Marchant

11/26/2021, 8:31 PM
@User Do you know the path opengalaxy uses to access the sky130 pdk? I'm trying to run magic with the pdk in opengalaxy.