An ecosystem as defined by Webster's
is a "system formed by the interaction of a community of organisms with their
environment". This describes perfectly the methodologies so common for analog
and custom IC design. Unable to strictly rely on automation or synthesis,
the custom design flow is chock full of interactive niche methodologies that
have become the differentiator of most analog IC suppliers. But, these
methodologies are only at their most effective when their interaction is made
as tight as possible. The tightness is required to provide the end user
the most cohesive design analysis possible. Moving "in and out" of the
design flow leads to big mistakes if not carefully monitored. But where
are the important touch points in a design flow? What provides the end
user with the right amount of cohesion without a cohersion to use
non-integrated tools adding risk to the schedule? Let me argue that
Cadence's Virtuoso custom design platform finds the right middle ground with
its built-in extensibility. The early developers of the Virtuoso custom
design platform understood the need for customization and built a solution that
was extensible through either C++ or Cadence's own SKILL programming
language.
Our customers have come to rely on
the extensibility of Virtuoso in several ways. Larger customers use it to link
in their own proprietary tools into the over all Virtuoso design flow to help
them differentiate themselves. These proprietary tools are often
customized to exploit the company's particular design flow needs, and are
usually considered ways for them to gain a productivity advantage in the
overall design methodology. The introduction of the OpenAccess database
further assisted this effort by removing "translation" barriers common to the
old methodologies, such as LEF/DEF. If the integrated tools could take
advantage of a common database, tighter coupling is possible. Cadence
takes advantage of this coupling by combining Virtuoso with Cadence's other
paltforms (Incisive, Encounter and Allegro) to provide larger macro-solutions.
Another way customers depend on the
extensibility is via links between Cadence tools and other commercially
available EDA tools. This is where the Cadence Connections program comes
in to help. While it is true that some of these members provide
competitive products to Cadence's, they are mostly working on products that
fill niches in the custom design flow where for business reasons, it doesn't
make sense for Cadence to be in the market. Those reasons can include
everything from it being too small (and therefore best served by a small
focused company) to the entrance barrier to get into that market is too high it
to be profitable for us.
Beyond integrations, Cadence does a
lot of work with other vendors that supply the larger ecosystem. The best
example is our work with the world's foundries to build Process Design Kits.
PDKs are the "rocket fuel" that accelerates the Virtuoso custom design
flow. However, this has become a controversial link point. There
are those industry pundits who argue that a single interoperable pCell provides
tighter linkage that going through the Virtuoso framework to SKILL
pCells. But at what cost? Remember, analog and custom designers
want accuracy combined with ease of use in the design flow. If pCells are
designed to the lowest common denominator, so that in theory it is
interoperable with every design tool, what is the value of the pCell? Due
to the physical properties of a pCell, I would argue for tighter integration
into the design flow you are using. As it is, quite a few customers feel
the need to rewrite existing PDK's to make them more accurate to the design
styles they are using. By providing the end-user with a pCell that is
even further abstracted from the truth, the end user is left with even a
greater amount of work to do. We don't think that is a plan for success and
have thus shuned efforts to drive the industry in this direction.
Cadence has provided the Virtuoso
ecosystem to our customers and our competitors for nearly 2 decades. As
we move through these tough economic times, you can at least be assured
that the value of Virtuoso as the hub of the custom ecosystem will be
maintained.