Re: gEDA-user: GSchem in CMOS Analog IC context?

[daledouglas@xxxxxxxxxxxxxx]

John,

You've hit the nail on the head: I'm trying to usurp a Cadence flow for a high frequency continuous time analog design. As such, I have a lot of problems to overcome, but a rough order looks something like:

1) download/build GSchem
2) find/build symbol library for TSMC XXX
3) find a way to convert netlist to Spice format compatible w/TSMC parameterization (W,L,f,m,Corners)
4) find a way to do Monte Carlo, even if only with deltaVTH numbers from Pelgrom or Kinget
.
.
.
99) find/build robust open source LVS flow

Yesterday I did #1. Today I'm working on #2. I would love to get a copy of the OpenIP library, thank you.

Are you saying that #3 is going to be harder than just downloading/building GNetlist?

Many thanks,
Dale Douglas
http://www.linkedin.com/pub/2/184/925

-----Original Message-----
>From: John Doty <jpd@xxxxxxxxx>
>Sent: Mar 8, 2009 12:05 PM
>To: gEDA user mailing list <geda-user@xxxxxxxxxxxxxx>
>Cc: daledouglas@xxxxxxxxxxxxxx
>Subject: Re: gEDA-user: GSchem in CMOS Analog IC context?
>
>
>On Mar 8, 2009, at 7:22 AM, Stuart Brorson wrote:
>
>> Hi --
>>
>>> Has anyone successfully used GSchem in an CMOS analog IC context? --
>>> I'm looking at a plain-vanilla +MIM TSMC CMOS process at the ~ 0.18
>>> to 0.35u node. Has anyone built symbols for the typical TSMC nodes
>>> (parameterized NMOS,CMOS,resistors with appropriate sheet resistance
>>> and tempco)?
>
>
>Dale, assuming you're using SPICE, the question is whether the  
>currently maintained gnetlist back end (spice-sdb) understands the  
>parameter names. A regular resistor symbol should work fine with the  
>right attributes.
>
>So, Stuart, does spice-sdb know how to transfer attributes to  
>parameters in the following syntax (ngspice)?
>
>General form:
>
>        RXXXXXXX n+ n- <value> <mname> <l=length> <w=width> <temp=val>
>        +        <dtemp=val> m=<val> <ac=val> <scale=val> <noisy = 0|1>
>
>
>>
>> Peter Kaiser in Germany has done some chip designs using gEDA.  Here's
>> the website he put up recording some of his tips, including some
>> symbols for instantiating devices:
>>
>> http://www.easyasic.com/
>>
>> You might try contacting him in person if you have questions.  His
>> e-mail addr is on his website.
>>
>> John Doty has also done mixed-signal designs using gEDA.  He has
>> published papers on his work, and has written an interesting gnetlist
>> back-end, all of which he has posted on his website.  I didn't see any
>> schematic symbols on his website, but here's a link:
>>
>> http://www.noqsi.com/home.html
>>
>> John is very active on the e-mail list, so I expect that he'll turn up
>> to provide more info to you soon.
>
>Gotta be less predictable ;-)
>
>Dale, I've done several design variations on my delta-sigma CCD  
>chains using 350 nm TSMC. However, I haven't gotten into careful  
>modeling of the resistors. I use very few resistors in these designs,  
>always in noncritical places. Gains are set by capacitor ratios.
>
>If you're interested, I've been working on symbols for professor  
>Ikeda's OpenIP (http://research.kek.jp/people/ikeda/openIP/). I can  
>send you an alpha version of that library if you wish (you get to  
>check them, as I've only used a subset), and I can answer specific  
>questions if you can't read the Japanese documentation.
>
>John Doty              Noqsi Aerospace, Ltd.
>http://www.noqsi.com/
>jpd@xxxxxxxxx
>
>



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