Hello, everyone:

        I'm trying to do a bandgap reference project myself. I downloaded the spec of this project from a
university website. however I couldn't find the spice model for it. I been searching on internet for quite some
time, no result so far. I'm wondering if anyone can help me with this? pointing out where  I can get it? preferably 0.25um.  also the bandgap circuit need BJT,  so the pnp or npn should be the parasitic device of
cmos. so the corresponding pnp or npn model should be deduced from cmos process, not from stand alone bipolar process. is this correct?  
        thanks a lot.

just_started

Hi,

device models are considered proprietary by the foundries and are not published on the web. If you are registered at a university, you should be able to ask a lecturer for accessing the design kits installed on their servers. Alternatively, as suggests Marc, you can register with MOSIS or Europractice, but this is only possible as a university or company, not as an individual, I believe. So, if you want to do this design "undercover", you can still find some device models on the web:
- this is the EKV model of a generic 0.15um process
http://www.eecs.berkeley.edu/~zyzhang/ee290c/Hspice/CDR/cmos_15.txt
- these are the generic models from J.Baker's book:
http://cmosedu.com/cmos1/book.htm
- on this page some bipolar parameters:
http://www.seas.upenn.edu/~jan/spice/spice.models.html

You are right about the bipolar models, the vertical device you use in a standard CMOS process is not comparable in performance with the optimized bipolar transistor in a bipolar or BiCMOS process. However, as you are not going to integrate this design and you just want a device model with exponential characteristic, these should work too.

Notice all these models are Spice models, you have to add a language statement at the beginning if you use Spectre.

Paul

Thanks a lot for all the response. I got 0.25um CMOS model from MOSIS. and PNP model from some
website. The BJT model may not be for the BJT in standard CMOS process. but I'm only trying to
the project for my own study. as long as I can get the idea, it'll be fine.

one more question though, I'm a ASIC design engineer but want to switch to analog design. I have studied
the analog circuit materials, I feel I actually understand the analog concept. I just need to do some design
projects to put on my resume so that I can apply for job. probelm is I currently don't have access to the
commercial tools, like Hspice or spectre. the simulator I  use is LTspice from linear tech. It's already
very good simulator for a free tool. However I feel it still lack some utilities compared to the commercial
tools. like spectre has PSS simulation, it can simulate 1-db compression point, IP3, phase noise etc. I know
I'm asking to much. but just in case if someone out there knows of a better simulator, even cost me some
money, not a lot though, I would appreciate it the info.

Hang

You can get WinSpice and LASI (for layout).  I don't think the fancy tools are necessary to help hone your skills.  Sch. capture would be nice though.  I've tried Electronics Workbench for home stuff but found it wasn't all that compatible with custom IC design.  Pretty good for home projects though!  They recently added a feature that lets you specify MOS aspect ratio, but the model level only goes to spice level 5, so it doesn't accurately handle stuff like BSIM4.