( DAC 01 Item 36 ) --------------------------------------------- [ 7/31/01 ]
Subject: Nassda, EPIC, Celestry, Tanner, Silvaco, Silos3, Mach TA, SPICE
SPICE & FASTER SPICE: For those chasing noise and SI issues, SPICE-level
sim accuracy is a must. The problem is that no matter how much SPICE sims
are speed up, they're still dog slow. If you're willing to be 1% to 5% off
from a true SPICE sim, the near-SPICE guys will give you a 100X speed-up.
Synopsys EPIC (PowerMill, TimeMill, etc.) owned this niche years ago, but
recently they've been slipping. It looks like all those ex-EPIC employees
at Nassda are successfully beginning to steal this niche from their old
employer, Synopsys!
"SPICE, etc.
Antrim Design sells a simulator that takes SPICE and Verilog AMS.
FTL Systems sells a simulator that takes VHDL, Verilog, the analog
extensions to both those languages, and SPICE. They have no plans for
C/C++ in the near future. They also can simulate on multiple nodes
like Provis. The digital <-> analog interface is defined via AMS specs.
Electronics Workbench sells a tool that can mix VHDL, Verilog and SPICE
(no analog HDL extensions?). The digital <-> analog interface is done
via a GUI. They do mostly boards or small ASICs.
Silvaco sells a large number of specialized tools. They say their
SmartSPICE tool is faster than Avanti's HSPICE. They also sell 2D
process and device simulators that allow "virtual wafer fab" - you can
supposedly predict the effect of process or device design changes.
ISE sells a tool to create SPICE models from a process description,
before you actually start fabricating a new process (or tweak an
existing one).
The standard in the SPICE arena is HSPICE, which Avanti now owns.
Intusoft makes a SPICE simulator that they claim is faster and cheaper
than their competitors and comes with a big library of models.
Applied Simulation Technology makes a package level SPICE tool.
Xpedion sells an RF simulation tool that can integrate into the
Cadence design environment.
Aplac sells an RF analog simulator, as well as board level RF tools.
Circuit Semantics, who originally sold software to characterize cell
libraries, has their own version of SPICE that they say is super
fast, but I don't think they sell it as a separate product."
- John Weiland, Intrinsix
"We have been using the Nassda HSIM simulator, and it works better than
PowerMill. It uses the SPICE deck directly, it doesn't require
fiddling with a config file each time to run different simulations,
and it seems to run 3x or more faster. We like it!
Newbies like Nassda give better, more personal support, than the
established "Big 4" EDA vendors (Avanti/Cadence/Mentor/Synopsys).
Just try to get an AE to come on-site, or even return your call! The
Big 4 would rather you spent big consulting bucks to get the tools
you bought from them to work."
- Michael Fliesler, AMD
"Nassada is better than the *Mill tools, but if you already own them it
is probably not enough better to switch (unless hierarchy is a big deal
for you like RAMs.)"
- [ An Anon Engineer ]
"Nassda's HSIM is still the high-capacity circuit simulator to beat.
Their tool is an absolute requirement when designing with big on-chip
memories. Synopsys' NanoSim is also attractive because of its
integration with VCS. There's room for both tools in companies like
ours, and we own both."
- Mike Carter of Mosaid Technologies
"Synopsys/NanoSim
Bundling of TimeMill, PowerMill, VCS/Ace, plus new technology for
high-capacity memory transistor-level simulation is Synopsys' response
to Nassda's HSim product. HSim has been evaluated by a number of teams
within our company. It's an improvement over TimeMill/PowerMill.
Synopsys NanoSim is able to simulate and analyze power simultaneously,
able to link in VCS for simulating strictly digital logic. Clear that
Synopsys is all but abandoning TimeMill/PowerMill, and is encouraging
customers to upgrade to NanoSim."
- [ An Anon Engineer ]
"The most promising tools in memory timing verification -
1. HSIM from Nassda, [capacity 1 billion transistors]
2. Nanosim from Synopsys, [capacity 256 million transistors]
3. Ultrasim from Celestry. [capacity 1 billion transistors]
None of the examples finished simulation on the floor."
- Raj Sayana of MoSys
"Biggest lie? It's a combo 3-way tie between Nassda, Mentor (MachTA),
Avanti (StarSimXT). All three had slides indicating that their tool
was the same amount (3-5x) faster than the other two tools on some
mysterious analog clock/PLL block sim from a large telcom company. All
3 had the same curve with the other two 2 identified as slower (the 3
tools rotated positions Nassda/Avanti/Mentor, Mentor/Nassda/Avanti, and
Avanti/Nassda/ Mentor) and appear to all use the same circuit at the
same customer! Looks like a tweaked claim to me at best."
- [ An Anon Engineer ]
"The Epic tools are getting pretty OLD when run against NEW designs.
Nassda looks very good if you just want a super SPICE. There aren't
many solutions to IR drop that really work for NEW designs so
Simplex should do very well.
I hear the Tanner tools are getting kind of expensive compared to the
Cadence tools they try to replace."
- John Szetela of AMD
"We looked at HSIM by Nassda, and to gain any significant speed
advantage on a PLL circuit, we had to sacrifice so much accuracy that
it was useless. Went with TimeMill by Synopsys, even though it was
harder to use (HSpice netlist must be translated before simulation.)
- Todd Moyer of Pixelworks
"Spice-Like Simulators:
These are tools that are close to SPICE in accuracy but simulate much
faster, so it is possible to analyze an entire ASIC (which would be
hopeless in SPICE). I believe the tools from Epic, which Synopsys
acquired, were the first tools in this category. They have tools to
do transistor level logic simulation, power simulation (without
layout), transistor level static timing analysis, and IR drop analysis
after layout is complete. Epic has lost market share and doesn't seem
to be advancing as fast as their competitors.
Nassda has lots of former Epic people in it. They have tools to
compete with Timemill and Powermill. They are working on a tool for
IR drop analysis, but it won't read the layout directly. Their
customers are split down the middle between analog and memory
designers, with a few digital people who are really concerned about
their clocks. They say they can simulate two write and two reads on
a 512 M DRAM (over 2 billion transistors) in 6 hours. Their tool uses
either table lookups or actual SPICE, depending on how critical the
net is.
Siliconcraft sells tools similar to Epic but says their tools are
10X faster and within 3% of SPICE.
BTA Technology has merged with Ultima to form Celestry. They have tools
to do hierarchical transistor level simulation and also to measure IR
drops. They compete directly with Epic and say they are faster.
Circuit Semantics sells tools for creating models of cells, custom
blocks or IP. They have a transistor level static timing analyzer as
part of the tools, but I don't think they sell it separately."
- John Weiland, Intrinsix
"Silvaco has SmartSpice, which I actually use. It's almost free. I
just don't understand how they can make money."
- Bill Cox of VI ASIC
"We have tried SimuCAD's Silos3 as a simple "analog Verilog" simulator,
and it works well for our purposes (mixed-signal Flash memories).
Some of the other tools, like MachTA or Verilog-MS are overkill. We
just want to run a lot of test vectors fast, to debug the design."
- Michael Fliesler, AMD
"I got a good demo of the Celestry (BTA-Ultima) tools and was impressed
with their extractor in speed and accuracy. Nautilus, Ultrasim, and
Clockwise are coming together nicely from the BTA-Ultima merger."
- Tom Moxon of Moxon Design
"Celestry Nautilus:
Nautilus is a full suite of signal analysis products offered by
Celestry. The Nautilus product suite consists of: Nautilus-DC
(delay calculator), Nautilus-SI (signal integrity), Nautilus-VT
(power analysis) and Nautilus-HCI (hot carrier). Nautilus is
offered as a complete solution and not as a point tool. However, the
sales person has informed us that Nautilus-SI can be purchased
separately. Key features:
* Noise analysis report with timing windows from PrimeTime. They
can also use the Nautilus-DC embedded in this product.
* Incremental SDF generation instantiating crosstalk induced delays.
* supports DSPF/SPEF with coupling caps.
* Multi-threading available.
On a side note, Celstry offers design services, where they help
customers build testchips for process characterization.
We were shown no demo of the product. I am usually concerned any time
a vendor makes just a presentation without a demo, especially at DAC.
The sales manager has offered to take one of our designs and run the
analysis for us."
- [ An Anon Engineer ]
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