( DAC 04 Item 27 ) --------------------------------------------- [ 02/09/05 ]
Subject: Paragon SE and Catena SiMetrix
DEATH TO VIRTUOSO! (Part II) -- Going for the cheaper seats and teaming up
with SiMetrix, Paragon SE is also a Virtuoso wannabe. Paragon was a DAC
newbie last year. It was rumored last year that Paragon has a customer
base in Asia, too.
Paragon IC Solutions
This EDA company has schematic capture, custom IC layout, DRC/LVS and
SI tools. Their target user is a Cadence IC designer or layout person
wanting a cheaper set of tools. No optimization or analog synthesis.
Development is done in China. The tools look and feel like Cadence,
except they don't use any Skill code just Tcl instead.
- Daniel Payne, Consultant
We looked at Silvaco, Tanner, Mentor, Cadence and Paragon.
Cadence wrote themselves out of the picture with a quote which they
claimed was stripped down to bare bones, but Cadence was still 5X what
we were willing to spend.
Mentor prepared a very interesting quote but was still above the amount
of money we had. (We are funded through consulting and grants.)
Silvaco had a reasonably complete set and we had some interest in the
device parameter extraction tool also, but there is always the Ivan
issue. (Who's he going to sue today - us?) Also, for the kind of money
we were talking about, we would only get full access to the cheap tools,
and for the more expensive pieces like the parasitic extraction we would
have to rent by the hour.
Tanner put together a complete quote including some prefabricated design
blocks. However we learned that these had not in fact been silicon
tested so we weren't sure how much value they added. The parasitic
extraction capabilities seemed extremely limited also - capacitance is
only vertical area based, no fringe terms, no wire to wire extraction.
I talked to one of their testimonial people, but he had only used the
layout tool, none of the rest of the suite. That didn't seem like a
whole-hearted endorsement. Another testimonial user said the tools
were good for small components but was dubious about whether the tools
would scale to a large design. We are aiming at a large chip, so a
non-scalable tool didn't seem like a good match.
For Paragon, we got a ringing endorsement from a trusted previous user.
(I don't want to give his name since I feel like we already imposed by
calling him up and chatting with him on a Friday night.) In addition,
our own kicking the tires felt pretty good. We read in a large GDS file
and it didn't choke. Poking around under the hood showed that the
parameterizable cells are all written in TCL and there is a lot of
programability.
The Paragon parasitic extractor is quite sophisticated according to the
documentation at least - it does field solver accuracy on sample cross
sections and then uses pattern matching to extract the parasitics of
the entire design. The tool is also Unix based which gave us a higher
comfort level in terms of being able to go in and fix whatever we needed
with awk, perl etc. Finally, the design kits for the foundry
technologies we needed were all ready to go.
Overall, we got a sense of solid engineering in the Paragon tool.
Whether this is borne out by experience, only time will tell.
We are just installing the Paragon tools as we speak.
- [ An Anon Engineer ]
We are just starting to use Paragon now, so, we are still very green!!
As a small company (our IC group just grew by 100% from 1 designer
to 2!!!), we were looking for an IC design tool that was a good
middle-of-the-road compromise between the 'low-end' tools (cheap but
limited), and the 'high-end' tools (can do everything but obscenely
expensive) and came to the conclusion that Paragon was the best bang
for the $$$ out there.
Some of the key points:
1. Open architecture (similar to Cadence) - you are not 'stuck' - you
can add capability by interfacing with other tools, simulators, etc.
2. Front to back integration with a 'design manager'.
3. Good verification tools (DRC/LVS) and LVS debugging tools. Can
import Dracula decks with minimal changes.
4. 2.5-D parasitic extraction capability - seems to work well.
Now, we just need to use their system for awhile...
- Patrick Mawet of Micro Encoder, Inc.
You asked for my opinion of how Paragon stacks up against its rivals
Cadence Composer, Spectre, Analog Artist, etc...
I used Cadence dfII tools for over 10 years and like them. I even liked
the support that I've had over the years, but I chose to go with the
Paragon tools at my new company. Primarily, it came down to lower cost
for similar functionality and the ability to work with the same data.
1) Similarity to Cadence: Since most custom IC designers use the Cadence
dfII environment, using Cadence or an environment similar to Cadence
will allow new designers and consultants to come up to speed quickly.
Anyone familiar with Cadence will understand how to use Paragon
instantly. Even the default binkeys and option forms (f3 button for
example) are similar.
2) Virtuoso/Dracula/Calibre lib compatability: Most foundries support
Cadence Virtuoso (creation) and Dracula/Calibre's DRC/LVS. Paragon
does a good job working or converting these files. EDIF from
Cadence worked flawlessly.
3) Functionality/bugs: For an analog designer, Paragon work well.
I have no idea how Paragon handles huge capacity, but the tools work
just great for our applications < 10K transistors).
4) Roadmap: Paragon is very responsive to bug and feature requests.
Most of my requests are put into the tool within 3 months. They just
don't say it, they do it. They intend to stay compatible with dfII
and Open Access. Makes it a low cost industry compliant tool.
5) Cost: Being a small company, we don't get the huge discounts and
economies of scale as the big guys. Also, our hardware of choice is
a laptop (flexibility, nightly simulation runs, consultants). If
licenses are going to be node-locked, they better not cost too much.
Functionality:
Library manager: simple, stable, Cadence-like
Schematic: As good as Cadence Composer. EDIF works. Stable.
Layout: Has similar capabilities to Virtuoso. Missing some elegant
features that can be found in Virtuoso-XL capabilities such as auto-
abutment, permutability, etc, but all of the needed functionality
is present.
DRC: On the fly warnings, zooms to error, etc. Works well. Reads
Dracula/Calibre decks directly.
LVS: Creates a schematic representation of the layout and netlist
for topologies that do not jive. Very troubleshootable. Reads
Dracula/Calibre decks directly.
RC Extraction: Sounds like a good story, but we still need to
investigate.
Analog Simulation: They don't have a SPICE simulator, but they provide
a basic simulation environment that also provides HSPICE and Spectre
netlists. I use the SiMetrix simulator that launches from the Paragon
cockpit. Schematic Crossprobing and op-point voltage backannotation
works well.
Digital/Mixed-Signal: Not there yet.
Would we buy Paragon again? After using the tool for a few months, we
bought it, then doubled the number of purchased licenses 3 months later.
- Cliff Wiener of Proteus
Paragon / SiMetrix Schematic Editor and Simulation:
For the past year and a half I have started my own independent company,
Alpine IC Innovations, LLC, which focuses on full custom analog IC
design and layout. I noticed that the CAD tool industry observed the
gapping hole of opportunity created by Cadence's outrageous asking
prices and many smaller companies were intent on getting some of this
market away from Cadence. I have been a Paragon tool user for just
under a year now. Before using Paragon I already had a schematic entry
tool packaged with the simulator I was and still am using, SiMetrix
( http://www.catena.uk.com ) Paragon tools now come packaged with
SiMetrix as the simulator however the Paragon tools can interface to
a number of simulators similarly to the Cadence Artist tools.
I first chose the simulator SiMetrix because of several factors,
convergence, speed, model support, support in general, event driven
digital simulation, behavioral modeling and of course price. SiMetrix
can also run on both Windows and Linux, the latter which I prefer
because of the abundance free tools and automation using shell scripts.
SiMetrix converges as well as Spectre in my opinion and simulates easily
as fast or faster than Spectre. It will also swallow pretty much any
transistor model without a problem, only occasionally requiring a slight
syntax change in a model parameter. SiMetrix's support is so good I
feel guilty for calling John Warner (the leader of the SiMetrix tool
support development etc. ). However, John and his tool are world class
and the tool is a complete steal from a pricing point of view. SiMetrix
has its' own schematic capture program which is quite good and capable
of most anything required by an analog IC designer. It also has great
capability in discrete designs and switching power supplies. SiMetrix
has a scripting language as well allowing for automating simulations and
post processing. The tool is accompanied by excellent and concise
documentation for the user interface, simulator and schematic editor as
well as script language. SiMetrix only supports the front end design
(schematic and simulation) and does not have an associated layout editor
and verification suite. Catena, which is the parent company of the
Catena LTD which sells SiMetrix, does offer a layout and verification
tool suite that is very well integrated with SiMetrix allowing cross
probing etc. This LAYTOOLS suite is developed in Germany and runs only
on Windows. This now leads me to the Paragon tool suite.
Since my company provide for complete analog IC design and layout, I
needed a good layout editor and verification tool which also was
designed from the start to be well integrated with the schematic entry
tools, much like that of the Cadence tools. This is where Paragon
shines. It married the popular user model and design flow style of
Cadence and created a completely new incarnation for performing
essentially the same functions, although in a much simpler fashion. If
you already know how to do analog chip design using Cadence, then it is
a snap to switch to Paragon since it is set up in a very similar but not
identical fashion. Paragon can easily perform all the primary tasks
from concept to tape out of analog blocks and has chosen to focus on the
analog design flow. With a much narrower focus than Cadence, the tool
was designed to be infinitely less complex than the Cadence suite while
performing the same tasks, often at much higher speed and greater
flexibility. The Paragon suite can easily interface to many different
simulators and can create netlists in any format easily. Rather than
use the CDF style approach to allow different netlisting options, SE
supports different netlists for a number any arbitrary view of a cell
using a simple text file to define the syntax for each different type of
netlist that may be required. This file is typically a one-liner and is
so obvious to use it virtually requires no documentation to understand
what to type in for the netlist syntax. So that one aspect saves
probably a couple of weeks for each time a new process flow is created
since getting the netlisting correct takes a couple of hours instead.
This means you don't have to write extensive Perl scripts to FIX the
netlist generated by the tool since it is always correct when generated.
For simulation with the Paragon tools, I use SiMetrix which is
integrated in with the Paragon tool suite allowing cross-probing of
simulations referenced graphically to the schematic. The Paragon user
interface has built in the primary plotting, graphing and post
processing required for most simulations. One can also use the built in
post processing of SiMetrix as well. SiMetrix offers a GUI to enable
95% of any type of common analysis of simulation results including Monte
Carlo and Performance Analysis ( plotting an arbitrary output parameter
as a two dimensional function of either time, frequency etc and a sweep
parameter such as temperature, voltage, model corner settings. I
originally chose SiMetrix because of its' scripting language allowing
infinitely complex post processing, however, I find that I rarely write
scripts for this since most every analysis or plot I would like to see
is built in to the tool already.
The capabilities of the Paragon schematic editor and library manager
provide the same functionality as that offered by the Cadence suite.
However there are some additional features Paragon offers which are
beyond that offered with Cadence. I have already mentioned how
different cell views are netlisted and syntax is controlled with a
simple text file. Another great feature of the Paragon tools is the
ability to completely generate a schematic from a CDL netlist. This is
pretty amazing. You can give it a hierarchical CDL netlist and the tool
will create all of the necessary symbols, leaf cell schematics and
higher schematics automatically. One can then easily simulate from this
schematic database and cross-probe the results for analysis. The
alternative is digging though a netlist by hand to find nodes; yuk.
Passing parameters though the hierarchy is also a snap. Of course, a
very important feature is that many of the menu setups are very similar
(but not identical) to that of Cadence Composer so it is extremely easy
to find your way around. If you already know Composer, you can be up
and running with SE in hours. One an easily assign their favorite key
bindings separately for the Design Manager, Schematic Editor, Layout
Editor etc.
Though beyond the scope of this requested information, I must mention
that the Paragon layout editor is great. The one Cadence tool that I
though was pretty good from the start was Virtuoso, the layout editor,
with the exception of the Display Resource Editor for associating colors
and patterns to different layers. LE, the Paragon layout editor is also
extremely easy to use if you already are familiar with Cadence
Virtuoso. It too is not identical to Virtuoso but was designed from
scratch with a similar use-model as that of Virtuoso. Setting up a
technology file with the Paragon tools is very simple in addition, LE
has all of the path stitching, schematic driven layout features offered
in Virtuoso. Parameterized layout of NMOS, PMOS, resistors etc is also
possible and much more stream-lined than in the competition tools.
Probably one of the biggest areas that LE shines is in speed while
viewing large layouts. I run a Pentium 4, 2.4GHz, 1GB ram, no-name
machine on Redhat 9 and it is probably twice as fast as Cadence on any
of the Sun or HP workstations. Not bad for 250$ of hardware and a free
operating system. Also, Paragon installs in about 5-10 minutes and you
don't have to be a Unix/Linux wizard to do it. The DRC and LVS checking
is also great. It seems to be every bit as fast as Calibre / Assura for
my designs so far. Paragon's support for various foundries is also
expanding quickly.
The Paragon tools are developed in China and supported and sold by a
highly efficiently team in Irvine California. They don't have all of
the fancy web-based bug tracking that Cadence has and don't need it
because the software works "out of the box". Occasionally when I do
find a bug or need urgent help I have always been completely thrilled by
the knowledgeable support from the dedicated staff at Paragon. As is
the case in many situations, my problems are due to "Pilot Error" and
not a bug in the tools. Even so, the Paragon staff has always been
available and eager to help me when I am in a panic (even over the
recent Christmas holidays), whether I was having a problem with the tool
itself or just usage.
Any tool suite has areas of improvement; Paragon less than others.
Paragon's tools come with documentation that is adequate for most
situations as well as great examples. It also is true that, in
principle, no documentation can ever be exactly what the user wants and
is always a bit behind the latest tool features. That being said I
look forward to more extensive documentation of the new tool features.
To Paragon's credit, their support via phone or email is more than
adequate when I can't figure something out or I am acting retarded.
The remaining area of improvement would be to include a simple user
programming / scripting interface to further customize the tools for
one's individual preferences. This is on Paragon's road map and should
be available soon. And, I suppose the icing on the cake of my wish list
would be to offer a simple digital place and route tool. With all of
these points considered, Paragon's pricing has allowed it to be within
the range of small companies while it achieves state of the art CAD for
mainstream analog IC design, simulation, layout and verification. I
have taken the tools all of the way though all phases of IC development
on several chips now and would highly recommend it to anyone as my first
choice of full featured analog IC CAD solutions with equal performance
of that offered by the very expensive traditional design tools.
- Brad Davis of Alpine IC Innovations, LLC
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