On Thu, 25 Apr 2019 13:04:10 -0500, Sem Jansen wrote:
> What I want, really, is just what anyone at home would want I would
> think which is to have free analog design schematic capture software
> which just does schematics and spice and then does basic layout of
> something no larger than about 300 devices and then a quick basic drc
> and lvs if that also exists.
>
> I'm not going to actually put the GDSII on a shuttle - I just want to do
> it for the fun and education and experience of designing a working small
> cmos PLL or OpAmp or something of that small size.
>
Years ago, when I was getting into this to work with a MUCH more
experienced guy who was actually going to be doing the IC design, and I
was going to be doing the overall systems design, was to load Mentor
through our university license, and work through a small tutorial.
I think I built a 2-input CMOS gate in schematic, then implemented the
several transistors and simulated it. It took me a couple days to get
that far. But, once I had done that, I was a lot more able to understand
the other guy's language.
> I could write the book if it doesn't exist, so the software is mostly
> what I need, I guess, if the book with software doesn't exist.
>
> If the software is open source, then I could even include it maybe in a
> cdrom with the book if I write it.
>
> It's not hard to design an analog ic of a small size if you have those
> tools but they cost too much for a home user.
>
> I hadn't thought about the pdk problem until you mentioned it where
> MOSIS might be the right way to go if they'll let me use it for free.
>
If you are at a university, I think you could do this at no cost, through
their university education program. Otherwise, I'm pretty sure NO WAY!
> I wonder if MOSIS would want me to write a book for them for home users?
NO! "Home users" just does not make any sense. MOSIS was set up to do
two things. One, get special-purpose ICs fabricated at reasonable cost,
and also to offer students the opportunity to have a thesis design
fabricated so they could see where they goofed. MOSIS was originally
funded largely by the Defense Department's DARPA program, but has largely
been downgraded to have to scratch for $ to keep open.
We get a few more chips made than the minimum, our chips are not really
all that small, we use old, much cheaper processes, and our chip batch
typically runs about $40K. Also, it typically now takes about six months
to get our chips back from the fab. I just don't see why MOSIS would
have any interest in people who can't afford to actually have the chips
fabbed.
Jon