I like Ken's paper
http://www.designers-guide.com/Design/top-down.pdf. However, for complicated mixed signal designs, probably it is worth to develop soft and hard macros, IP re-use, and so on (in order to speed up development.) So it will be not pure top-down design. Say, digital designers have advanced methodology, based on the IP re-use, Virtual Socket Interface (VSI), etc. They put well established rules in "Reuse Methodology Manual for System-On-A-Chip Designs" (by Michael Keating, Pierre Bricaud). Also the VSI site (http://www.vsi.org/) is very comprehensive.  Do we have some similar documents/papers in the analog and mixed signal design emphasis? Thanks.

I agree with Ken.  I think that we're a long way away from having truly soft analog IP.  However, I think that hard analog IP does make sense today, and I think that there are opportunities for "firm" analog IP today as well to gain some of the advantages of re-use.

Chapter 8 of

• H. Chang, L. Cooke, M. Hunt, G. Martin, A. McNelly, L. Todd, Surviving the SoC Revolution, Kluwer Academic Publishers, 1999.

discusses some ideas on what firm and hard analog IP would be.

Also, you mentioned the VSI in general.  Just to be certain, I think that the most applicable specification would be the "Analog/Mixed-Signal Extension Version 2 (AMS 1 2.x)".  This describes in detail what an IP provider of hard analog IP would have to deliver to an IP integrator for the IP integrator to be successful.  I believe that even if one went with "firm" IP, that ultimately the delivery of it to a mostly digital SoC would require that it be delivered as "hard" IP and thus this specification would still be applicable in part or in whole.

-Henry

Hard macros are a proven viable methodology in IP re-use.
Even there, you run into problems with noise in the applications environwement.

Design re-use across foundry processes is generally not viable for analog designs.
Too many changes in subtle things mess the process up.

Jerry