buchs@MAYO.EDU (Kevin J. Buchs) (08/31/90)
We need to do some large SPICE simulations in terms of devices and simulation time. We really want to do a digital timing simulation of a circuit up to the size of a .5K gate array. Does anyone have experience in this and would be willing to lend some pointers? Note, we are not dealing with CMOS but GaAs BJT devices. ------------------------------------------------------------- Kevin Buchs Internet: buchs@mayo.edu Mayo Foundation Is this my life or is it just an Rochester, MN 55905 incredible, high-speed, simulation? (507) 284-0009 -S. R. Cleaves -------------------------------------------------------------
grege@gold.GVG.TEK.COM (Greg Ebert) (08/31/90)
In article <9008301934.AA11065@fermat.Mayo.edu> buchs@MAYO.EDU (Kevin J. Buchs) writes: >We need to do some large SPICE simulations in terms of devices and >simulation time. We really want to do a digital timing simulation of a >circuit up to the size of a .5K gate array. Does anyone have experience >in this and would be willing to lend some pointers? Note, we are not >dealing with CMOS but GaAs BJT devices. My $0.02: I did a simulation of a large CMOS adder in HSPICE and the execution time seemed to have an exponential dependency upon circuit size. I broke-down the circuit to sub-blocks which would be optimized. Starting from the input, I plotted the output signals, which were loaded by capacitors (CMOS). After I was satisfied, I used the PWL (piecewise-linear) function to generate the input to the next stage. After the whole monster was 'optimum', I ran HSPICE on the whole enchilada, and went home for the weekend. I was a bit pessimistic with my piece-by-piece approach. One thing you might want to know is that polysilicon runs don't need to be modeled as distibuted RC networks, at least in digital simulations. I used a 'pi' network, with shunt capactitors equal to 1/2 the trace capacitance, and a series R equal to the resistance of the entire run. I also compared to 5 and 7 element networks, and got negligible differences in overall speed. As I stated, this was for CMOS, but you might be able to use this for GaAs.
jge@jason.cs.unc.edu (John Eyles) (08/31/90)
>In article <9008301934.AA11065@fermat.Mayo.edu> buchs@MAYO.EDU (Kevin J. Buchs) writes: >>We need to do some large SPICE simulations in terms of devices and >>simulation time. At the risk of sounding like a broken record, you might want to take a look of CAZM, the simulator built by the Microelectronics Center of North Carolina. It's a LOT faster than SPICE (roughly 10X) and gives very similar results. It uses SPICE models and circuit descriptions but has a considerably nicer command language. It also has better convergence behavior. I think they now support the kinds of devices you mentioned. For details try kenkel@mcnc.org (Steve Kenkel).
positron@cosmic.berkeley.edu (Shigeki Misawa) (09/01/90)
>>In article <9008301934.AA11065@fermat.Mayo.edu> buchs@MAYO.EDU (Kevin J. Buchs) writes: >>>We need to do some large SPICE simulations in terms of devices and >>>simulation time. >At the risk of sounding like a broken record, you might want to take a >look of CAZM, the simulator built by the Microelectronics Center of >North Carolina. It's a LOT faster than SPICE (roughly 10X) and gives >very similar results. It uses SPICE models and circuit descriptions but >has a considerably nicer command language. It also has better convergence >behavior. I think they now support the kinds of devices you mentioned. >For details try kenkel@mcnc.org (Steve Kenkel). So what is CAZM, what does it run on, is the source code available, what language is it written in , how much does it cost, who uses it, and where can I get a copy? Shigeki Misawa - UCB Physics Department.
richards@mcnc.org (William R. Richards Jr.) (09/01/90)
> >At the risk of sounding like a broken record, you might want to take a > >look of CAZM, the simulator built by the Microelectronics Center of > >North Carolina. It's a LOT faster than SPICE (roughly 10X) and gives > >very similar results. It uses SPICE models and circuit descriptions but > >has a considerably nicer command language. It also has better convergence > >behavior. I think they now support the kinds of devices you mentioned. > >For details try kenkel@mcnc.org (Steve Kenkel). > > So what is CAZM, what does it run on, is the source code available, what > language is it written in , how much does it cost, who uses it, and where > can I get a copy? > > Shigeki Misawa - UCB Physics Department. CAzM from MCNC can be had for a song ($150 for educational inst.). jeri@mcnc.org may be contacted for licensing information. It runs on most UNIX machines, the source code is comes with the binaries, it is written mostly in C, over 50 site licenses have been issued and you can get a tape directly from MCNC. If you want some more technical info, Gary Nifong (gbn@mcnc.org) may be contacted... -------------------------------------------------------------------------------- Bill Richards MTS Phone: (919) 248-1452 Microelectronics Center of North Carolina Fax: (919) 248-1455 PO Box 12889 RTP, NC 27709-2889 e-mail: richards@mcnc.org
jge@jason.cs.unc.edu (John Eyles) (09/01/90)
In article <1990Aug31.180859.17072@agate.berkeley.edu> positron@cosmic.berkeley.edu (Shigeki Misawa) writes: >So what is CAZM, what does it run on, is the source code available, what >language is it written in , how much does it cost, who uses it, and where >can I get a copy? Please direct inquiries about CAZM to MCNC. I believe Steve Kenkel is the correct person (kenkel@mcnc.org). I'm not officially connected with MCNC, just a very happy user of CAZM. Partial atempts at answers: it's a circuit simulator, uses charge and current tables to perform the simulations runs on Convex, Vaxen, 3100, probably a lot else (I'm pretty sure not PC) it's written in C colleagues and I have used it to design several large (1/2 million transistor) CMOS designs, designed to run at 40 MHz worst case; all designs worked on first silicon at speed (but fab was nominal) in practice, we rarely used CAZM on circuits of more than 1000 devices, but I think the MCNC folks claim to have used it on 10's of 1000s of devices But, like I said, talk to them, esp. for availablity, source, cost, etc.