Which commercial simulator is best?

[Stuart Brorson]

Hello --

Regular readers of this froup will probably recognize me as a
something of a free software partisan. Therefore, this question may
come as a suprise. However, I am seriously interested because I may
soon be in a position where I must order a top-notch, commercial SPICE
package to do some intense circuit simulation work.

My question is: what is the best commercial grade SPICE simulator out
there? My requirements are:

* I want to draw my schematic, export a netlist & simulate it. I
would like very much if I could place a marker on a node & see the
corresponding trace (like in MicroSim Schematic with SPICE, or in
LTSpice). What packages do that?

* I would prefer if the same package could be used for layout, or at
least export a netlist which could be used for layout. This
eliminates Electronics Work Bench, AFAIK. (I last used EWB 5 years
ago, so maybe you can now do layout with the package.)

* I will want to do a lot of noise analysis. Are any of the SPICEs
optimized for this kind of work?

* I prefer to use Linux, but will use Windoze or Slowlaris if
required. (Windows prefered over Slowlaris.)

* I will need to run vendor .cir files. Therefore, the simulator
must be able to use external models.

* I don't like binary (proprietary) file formats 'cause I often want
to run Perl scripts on the schematic files. Therefore, I would
prefer if the program could export text-based schematic and layout
files.

Does anybody have opinions about the offerings of Protel, Cadence,
Mentor, et al? Which is the best? Now is the chance for all the EDA
marketeers and sales guys lurking out there to push their wares. (And
yes, Jim, I know that you are a MicroSim PSpice partisan, but Cadence
is gonna EOL it real soon now, so I can't get on that train! :-( )

Thanks for any and all opinions.

Stuart

 

[Mike Engelhardt]

Stuart,

My question is: what is the best commercial grade SPICE simulator out
there? My requirements are:

I don't think you'll find any commercial SPICE simulator with
performance better than LTspice's.

* I would prefer if the same package could be used for layout, or at
least export a netlist which could be used for layout. This
eliminates Electronics Work Bench, AFAIK. (I last used EWB 5 years
ago, so maybe you can now do layout with the package.)

Interface to layout is LTspice's schematic capture's weakest point.
While it exports netlists for layout Accel, Algorex, Allegro, Applicon
Bravo, Applicon Leap, Cadnetix, Calay, Calay90, CBDS, Computervision,
EE Designer, ExpressPCB, Intergraph, Mentor, Multiwire, PADS,
Scicards, Tango, Telesis, Vectron, and Wire List, you will have to
make symbols for the target layout package with pinouts that agree
with LTspice's.

* I will want to do a lot of noise analysis. Are any of the
SPICEs optimized for this kind of work?

SPICE's are pretty similar here in that they all do linear
noise analysis. LTspice's only advantages here is that you
can cross probe the noise contribution from components and
it has universal opamp model that lets you specify the noise
in terms of equiv. input noise current and voltage densities
and corner frequencies. I extended the underlying SPICE
algorithm for that and I don't think any other SPICE has
it. If you're working with opamp-based preamps, then LTspice
will definitely analysis noise easier and more accurately then
anything else. Another possible noise issues to look for is the
noise level MOSFET parameter, nlev, which LTspice does implement,
but that doesn't affect BSIM, so it's a bit obsolete.

* I prefer to use Linux, but will use Windoze or Slowlaris if
required. (Windows prefered over Slowlaris.)

LTspice runs fine on Linux. LTspice's 64bit address space for
waveform data even works on Linux.

* I will need to run vendor .cir files. Therefore, the simulator
must be able to use external models.

Covered. Best non-Cadence PSpice compatibility available plus
the ability to run most hspice targeted foundry models.

* I don't like binary (proprietary) file formats 'cause I often want
to run Perl scripts on the schematic files. Therefore, I would
prefer if the program could export text-based schematic and layout
files.

LTspice's schematics and symbols are ASCII. Waveforms are usually
binary and compressed, but there is a free 3rd party utility to
extract the data to ASCII.

--Mike

 

[Stuart Brorson]

Mike Engelhardt <pmte@concentric.net> wrote:
: Stuart,

:> My question is: what is the best commercial grade SPICE simulator out
:> there? My requirements are:

: I don't think you'll find any commercial SPICE simulator with
: performance better than LTspice's.

Thanks for your response, Mike. I will indeed be using LTSpice as
part of my work. And I don't doubt that it's probably the best out
there.

However, (and yes, this is stupid) I would look like an irresponsible,
long-haired & wild eyed lunatic (which may perhaps be the case) to
take on a new job & insist to a new boss who doesn't necessarily
follow the field that the best SPICE simulator is something you can
download off the web for free. Corporate politics being what they
are, it's better to spend some money for a high-end commerical package
in order to look sane and sober.

In any event, I will undoubtedly compare the results of whatever
commercial simulator we get to the results of LTSpice. It only makes
sense to check one's results against a high-quality benchmark. . . . .

:> * I will want to do a lot of noise analysis. Are any of the
:> SPICEs optimized for this kind of work?

: SPICE's are pretty similar here in that they all do linear
: noise analysis. LTspice's only advantages here is that you
: can cross probe the noise contribution from components and
: it has universal opamp model that lets you specify the noise
: in terms of equiv. input noise current and voltage densities
: and corner frequencies. I extended the underlying SPICE
: algorithm for that and I don't think any other SPICE has
: it. If you're working with opamp-based preamps, then LTspice
: will definitely analysis noise easier and more accurately then
: anything else. Another possible noise issues to look for is the
: noise level MOSFET parameter, nlev, which LTspice does implement,
: but that doesn't affect BSIM, so it's a bit obsolete.

This is very cool. Thanks!

:> * I prefer to use Linux, but will use Windoze or Slowlaris if
:> required. (Windows prefered over Slowlaris.)

: LTspice runs fine on Linux. LTspice's 64bit address space for
: waveform data even works on Linux.

The last time I used LTSpice on Linux I had to run it under Wine.
This was back in March or April. Has that changed?

Thank you! And kudos again for all the fine work on LTSpice!

Stuart

 

[Chuck Harris]

Hi Mike,

So, if you develop under linux, why won't you release a
linux version of LTSpice?

The GPL will allow you to do so without compromising your
proprietary code. GPL only requires you to release the
source for projects that are *based* on GPL'd projects, not
for projects that are *compiled* with GPL'd compilers and
linked to GPL'd libraries.

It'd be a great xmas treat for all us linux folk. Wine works,
but it sure stinks up the place with essence of Bill.

-Chuck Harris

Mike Engelhardt wrote:

Stuart,


:> * I prefer to use Linux, but will use Windoze or Slowlaris if
:> required. (Windows prefered over Slowlaris.)


: LTspice runs fine on Linux. LTspice's 64bit address space for
: waveform data even works on Linux.


The last time I used LTSpice on Linux I had to run it under Wine.
This was back in March or April. Has that changed?


No it hasn't. I understand the trepidation. When Linux was my
primary development system, I really didn't want to install WINE
on it. I only got involved with WINE so I could run LTspice on
Linux. But you can install WINE on Linux without messing up
anything else and LTspice doesn't require WINE tweaking to run.
The simulation speed is the same. Graphics is slightly slower,
but still good because LTspice only uses direct screen writes
except for some bitbliting in the symbol editor.

--Mike

 

[Mike Engelhardt]

Stuart,

:> * I prefer to use Linux, but will use Windoze or Slowlaris if
:> required. (Windows prefered over Slowlaris.)

: LTspice runs fine on Linux. LTspice's 64bit address space for
: waveform data even works on Linux.

The last time I used LTSpice on Linux I had to run it under Wine.
This was back in March or April. Has that changed?

No it hasn't. I understand the trepidation. When Linux was my
primary development system, I really didn't want to install WINE
on it. I only got involved with WINE so I could run LTspice on
Linux. But you can install WINE on Linux without messing up
anything else and LTspice doesn't require WINE tweaking to run.
The simulation speed is the same. Graphics is slightly slower,
but still good because LTspice only uses direct screen writes
except for some bitbliting in the symbol editor.

--Mike

 

[Mike Engelhardt]

Chuck,

...I understand the trepidation. When Linux was my
primary development system, I really didn't want to install WINE
on it...

So, if you develop under linux, why won't you release a
linux version of LTSpice?

When I said, "When", I meant "Way Back When." I used to
develop on Linux years ago when I wrote UNIX-based
simulators and was the first person to get SPICE running
on Linux, about a dozen years ago. When doing UNIX/X
development, it was useful to cross develop on multiple
platforms to find as many problems as soon as possible. I
guess I get that on Windows just keeping things running
on 95/98/Me/NT/2K/XP/WINE. They all handle memory
differently, so problems show up at different times in
each.

--Mike

 

[Frank Miles]

In article <brsit6$6gg@dispatch.concentric.net>,
Mike Engelhardt <pmte@concentric.net> wrote:

Stuart,

:> * I prefer to use Linux, but will use Windoze or Slowlaris if
:> required. (Windows prefered over Slowlaris.)

: LTspice runs fine on Linux. LTspice's 64bit address space for
: waveform data even works on Linux.

The last time I used LTSpice on Linux I had to run it under Wine.
This was back in March or April. Has that changed?

No it hasn't. I understand the trepidation. When Linux was my
primary development system, I really didn't want to install WINE
on it. I only got involved with WINE so I could run LTspice on
Linux. But you can install WINE on Linux without messing up
anything else and LTspice doesn't require WINE tweaking to run.
The simulation speed is the same. Graphics is slightly slower,
but still good because LTspice only uses direct screen writes
except for some bitbliting in the symbol editor.

Can you (or someone else) recommend particular versions of wine?
The debian versions I've tried won't run LTSpice.

-frank
--

 

[Jens Tingleff]

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Stuart Brorson wrote:

Mike Engelhardt <pmte@concentric.net> wrote:
: Stuart,

:> My question is: what is the best commercial grade SPICE simulator out
:> there? My requirements are:

: I don't think you'll find any commercial SPICE simulator with
: performance better than LTspice's.

Mike: Do you include programs with none or only weak links[1] to Bekeley
Spice in that statement?

AFAIK, loads of interesting algorithms were never in a Berkeley produced
chunk of code, e.g. transient noise (Eldo) or pseudo-transient DC ramping
(originally a feature of the Philips internal Spice-like simulator, I
believe), EKV transistor models (supported by HSpice, Eldo and Smash, at
least), etc etc etc.

Just curious.

However, (and yes, this is stupid) I would look like an irresponsible,
long-haired & wild eyed lunatic (which may perhaps be the case) to
take on a new job & insist to a new boss who doesn't necessarily
follow the field that the best SPICE simulator is something you can
download off the web for free. Corporate politics being what they
are, it's better to spend some money for a high-end commerical package
in order to look sane and sober.

I've never met a *good* engineer who could not work with a quality simulator
(even in preference to one he knows better). If the boss doesn't follow the
field (e.g. if you're the only person who would be using a simulator) then
a *good* boss would let you chose your tool. If there are already others
working with simulators, then only a *bad* boss would let a new engineer
start using a different tool (IMHO) - using more than one tool for the same
mission critical task seems like a quality nightmare, to me.

Best Regards

Jens

[1] I tend to assume that HSpice was only based on Spice 2g6 and branched
off from there, and I have no idea if Smash, Eldo or Aplac have any traces
of Berkeley Spice code in 'em


- --
Key ID 0x09723C12, j.tingleff@ieee.org/jens_tingleff@yahoo.com
Analogue filtering / 5GHz RLAN / Mdk Linux / odds and ends
http://www.imaginet.fr/~jensting/ +44 1223 211 585
"I write with a goosefeather dipped in venom" Waldo Lydecker 'Laura'
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[Mike Engelhardt]

Frank,

Can you (or someone else) recommend particular versions of wine?
The debian versions I've tried won't run LTSpice.

Sorry to hear that. LTspice was tested on Linux RedHat 8.0 with
WINE version 20030219. While I didn't think LTspice is WINE-
version sensitive, that is the version I have in one of my office
machines as a test bed for Linux/WINE verification. Maybe
Uwe B.(if you're reading) can help.

--Mike

 

[Jim Thompson]

On 18 Dec 2003 19:16:22 GMT, fpm@u.washington.edu (Frank Miles) wrote:

[snip]

Can you (or someone else) recommend particular versions of wine?
[snip]
-frank

Yellowtail (Australia) Chardonnay or Shiraz are my current best buys.
(Like 2 bottles for $11 plus a 10% discount for a six-pack ;-)

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice480)460-2350 | |
| E-mail Address at Website Fax480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.