kenkel@mcnc.org (Stephen Kenkel) (09/27/88)
CAzM (Circuit Analyzer with Macromodeling) is a circuit simulation
tool developed jointly by Duke University and the Microelectronics
Center of North Carolina. CAzM is superior in speed, stability and
convergence to the industry standard simulator, SPICE.
CAzM is now being offered to interested users on a cost-recovery
basis (see below).
CAzM uses sophisticated numerical techniques including look up tables
and an automatic time step adjustment scheme to ensure an accurate and
fast simulation. CAzM is up to ten times faster then SPICE for average
sized circuits (100-200 transistors) and the speed advantage tends to increases
as the number of circuit elements increase. CAzM has excellent convergence
properties. Circuits containing as many as 20,000 transistors have been
simulated successfully.
CAzM is a table based simulator. The tables contain charge and steady state
current information about each device in a circuit. These tables can
be measured directly, generated by a device simulator such as PISCES, or
built in models can be used. Built in models are available for standard
elements such as resistors, capacitors, and diodes.
Available MOS models include SPICE level I and II current equations and the
Ward-Dutton charge equations. The next release of CAzM (available early 1989)
will include Level III, IV (BSIM), JFET, and BJT (bipolar) models.
CAzM is netlist compatible with SPICE, with the extension that
node names can be alphanumeric. The command language is similar
to SPICE, but includes additional commands for specifying waveforms.
CAzM runs on a variety of UNIX platforms including VAX, Convex, and
Sun's (2, 3, and 4). CAzM is the standard circuit simulator used
at the Microelectronics Center of North Carolina and its Participating
Institutions for all chip designs.
CAzM is available on an "as is" basis, under a site wide license
agreement from MCNC.
The cost is:
175.00 Universities & Non-profit organizations
275.00 Foreign " " " "
800.00 Commercial
900.00 Foreign Commercial
Licensing information could be obtained from:
Jeri Williams
Software Distribution Coordinator
MCNC
Post Office Box 12889
RTP, NC 27709
(919) 248-1938
arpa: jeri@mcnc.org
uucp: decvax!mcnc!jeri
Technical inquiries should be addressed to:
Dr. Stephen Kenkel
MCNC
Post Office Box 12889
RTP, NC 27709
(919) 248-1972
arpa: kenkel@mcnc.orgjp@unc.cs.unc.edu (John Poulton) (04/14/89)
There has been some discussion lately in this newsgroup about circuit simulators that might be "better" than SPICE by some measure. I'd like to contribute our recent experience with a simulator called CAzM, developed by a collaboration between Duke University CS (Don Erdman, Don Rose) and the Microelectronics Center of North Carolina (Gary Nifong, Ravi Subrahmanyan). We've been using this simulator to develop a pair of CMOS IC's with fairly aggressive speed and density requirements and have found CAzM to be extremely useful and quite robust. Essentially every one of the hundred or so cells in these designs has been thoroughly simulated, many across a variety of process, voltage, and temperature conditions. If we had used SPICE, I doubt if we could have found either the patience or the machine cycles to finish this task. CAzM takes as input a standard SPICE-like circuit file (with alpha- numeric node names, of course) and its own simple simulation control commands, similar enough to SPICE that translation is easy. It models all the usual linear circuit elements and has employed the mos2 model for some time. Recently we have added and tested the mos3 model; MCNC will shortly release a version with bsim models and models for bipolar transistors. As we found by experience, the program is well constructed, and it's possible to add your own functions with virtually no risk of breaking already-existing ones. Except for certain numerical routines, CAzM is written entirely in C; it'll run on Sun and VAX UNIX platforms. CAzM is MUCH faster than SPICE for mosfet circuits. It uses the mos2/3/4 models to build tables of drain currents for each device size encountered, then, during transient analyses, interpolates currents from these tables, rather than computing them from the model for each time step. The result is that CAzM is about 10-60x faster than SPICE (by our comparisons), while producing essentially identical simulation results. It uses some advanced numerical techniques that make it very robust against convergence problems. We have only once or twice encountered the famous "time-step too small" problem with this tool, and I believe the MCNC/Duke team is currently ironing out the few remaining bugs that occasionally cause these problems. We'd be very interested in seeing this tool more widely distributed; more designer feedback usually produces better design tools. CAzM is available to universities at some nominal charge and is distributed by MCNC. If you're interested, get in touch with Steve Kenkel (kenkel@mcnc.org). John Poulton jp@cs.unc.edu