Legend Design Technology announces MSIM, a circuit simulator for layout-based characterization
SUNNYVALE, CALIFORNIA --May 31, 2002-- Legend Design Technology
is proud to announce the release of their latest product, MSIM a high
performance characterization-oriented circuit simulator. Together with
their other tools (SpiceCut (automatic critical-path circuit building tool)
and MemChar (automatic memory characterization tool)), MSIM completes the
flow providing industry's first comprehensive and automated solution to
the tedious and error prone processes associated with the characterization,
validation, and verification of SoC embedded memory.
Legend Design Technology's unique layout-based characterization flow
generates optimized timing and power models for use in system simulation
that reflect the reality of the silicon. Accuracy in characterization can
make the difference between a successful silicon spin (high yield) or a
failed one (low yield, time and cost of a re-spin). With the increasing
cost of a tape-out (.1 micron process approximately 2 million dollars) and
a shrinking time to market window, companies today can not tolerate a
In order to generate accurate timing and power models, characterization
through numerous circuit simulations with the appropriate Spice models are
required. The complete flow (SpiceCut, MemChar, MSIM) automates volumes of
simulations by supporting parallel computing for high throughput. Through
automation, integration, and concurrent simulation, companies can maximize
engineering time and minimize the uncertainty associated with SoC design.
Legend's Integrated Solution for Characterization and
SpiceCut is a critical-path circuit builder and
MemChar an automatic memory model generator. To speed runtime for hundreds
of simulations, SpiceCut automatically builds critical-path circuits from
the extracted layout. MemChar takes in the critical path netlists, Spice
Model, and data sheet specifications to automatically generate the simulation
stimulus and controls, (ie. set-up/hold time and minimum clock width).
MemChar's simulation manager then calls MSIM for running volume simulations
and measurements. Lastly, MemChar uses the data obtained from MSIM to build
the timing and power models (.LIB or .TLF). MemChar automates all processes
in the flow, including simulations and optimizations.
Quality Characterization for Preventing Glitch and Timing Soft
Critical timing in high performance designs is forcing
engineers to move from a schematic-based characterization flow to a more
realistic physical view which takes into account parasitics, coupling, and
distributed effects. Layout parasitic extraction is the driving force behind
the Legend Design Technology flow. This point is best illustrated in the
bisection model of a memory instance.
Traditional memory timing is characterized by a path difference.
Path difference will show a hard error viewable at the output pins,
but falls short of detecting racing conditions and glitches inside the
latches. 'Timing Soft Error' is the term associated with this extremely
difficult to see and often overlooked timing behavior.
MemChar's bisection model is built by a patented binary optimization
algorithm that determines the true set-up and hold times, effectively
removing the risk of failure associated with Timing Soft Error. It should
be noted that MemChar can automatically set up both Path Mode (fast) and
Bisection (high accuracy) characterization conditions.
Automatic Critical-Path Circuits Building from
It comes as no surprise to anybody with experience
characterizing embedded memory that the biggest bottleneck in the flow is
building the critical path circuits. This daunting task is extremely error
prone and time consuming and is becoming more challenging as technology
evolves. SpiceCut solves this problem by automatically building the
critical path circuits from the extracted layout and/or schematic. The
tool recognizes all nodes and latches, and takes into account all the
paths. Its built in RC reduction will produce equivalent circuits that
speed up simulations considerably. For large memory instances (>500K)
layout extraction could take an extremely long time, but SpiceCut is
able to function on a ring-shape extraction providing greater than a
10X speed improvement.
MSIM: Circuit Simulator for
SpiceCut and MemChar will set the stage
for memory characterization, but it is up to the circuit simulator
to get the results (timing, power). MSIM is Legend Design Technology's
latest product and is a true characterization oriented circuit simulator.
Its feature set and pricing model position the product perfectly for
memory characterization, but it is equally ideal for the characterization
of standard cell libraries.
MSIM combines a matrix-inversion based circuit simulator with RC reduction
to deliver unparalleled accuracy, performance and value. Proprietary RC
reduction technology enhances performance by reducing the size of the circuit
matrix due to RC's, thus improving convergence by transforming simulation
conditions from 'ill' to 'well'. MSIM supports all BSIM models from major
Benchmark results of MSIM with RC reduction on SRAM access time
is shown below
|Accuracy||3.41 ns||3.39 ns||0.59%|
|CPU Time||3,867 sec||317 sec||12.2 X|
* Standard means the most popular Spice simulator.
Parallel Processing for Performance
Technology is moving rapidly
from 0.18um, 0.15um, 0.13um and 0.10um. Along the way, the timing and power models
of memory become increasingly complex. For example, access time table of input
slopes versus output loadings is in the size of 3 by 3 for 0.18 um technology,
but 7 by 7 for 0.13um technology. Furthermore, each process variant such as
typical, slow and fast must have its own characterization. As such, the need
for volume simulations in memory characterization has become indispensable.
To provide high throughput, multiple MSIM jobs can be run concurrently in
characterization system. For example, to generate a 5 by 5 table of access time,
there are 25 MSIM simulation jobs required. The benchmark results below show
variations on concurrency on a register file.
| ||CPU Time||Gains|
|1 MSIM||7 Hours 17 Minutes||1.0 X|
|4 MSIM||2 Hours 8 Minutes||3.4 X|
|8 MSIM||1 Hour 13 Minutes||6.0 X|
|25 MSIM||18 Minutes||23.9 X|
Legend Design Technology is the first
company to provide a complete embedded memory characterization flow
based on layout extraction. The success enabling capability of the
tools will be realized in engineering productivity gain, successful
SoC fabrication, and achieving time-to-market targets.
MemChar, SpiceCut and MSIM are commercially available on Sun
Solaris, HP-UX and Linux platforms. Legend also provides
characterization services for memory validation and model
About Legend Design Technology, Inc.
Technology, Inc. provides tools and services for a complete
characterization solution of SoC designs, which includes embedded
memory and standard cell. With an emphasis on productivity and
value, Legend's success enabling products, SpiceCut, MemChar and
MSIM, revolutionize the time consuming and error prone processes
associated with characterization. SpiceCut can automatically build
critical-path circuits to reduce simulation time for
characterization, especially from post-layout extracted circuits
with resistors and capacitors. MemChar can automatically
characterize the memories and generate timing and power models. It
can generate 'true' setup and hold with 'glitch' prevention. MSIM is
a characterization-oriented circuit simulator with post-layout RC
reduction capability. With high accuracy, high speed and licensing
models, MSIM can provide excellent price-performance.
For more information, visit http://www.legenddesign.com/
For further information, contact:
Legend Design Technology, Inc.