Problems with SPICE models from vendors

R

Robert Baer

Guest
The LM324 model from TI works fine,but the one from National
Semiconductor is junk.
I tried numerous Analog Devices models for various rail-to-rail
opamps, and found that almost all i tried gave me the same kind of
cryptic square root error.
Those tried: AD8605, AD531, AD541, AD8552, and the AD8571; the only
one tried that did work was for the AD8614.
Now i would dearly like to have a set of models that were known to
work (and more or less correctly), but i need to get a working AD8605 model.
The sets i have came from the manufacturer created in the latter of
1992, and thus are not quite up-to-date.
However, the model for the AD8605 was downloaded via the web just
yesterday - implying the problem is not fixed.

Can anyone help?
 
"Robert Baer" <robertbaer@earthlink.net> schrieb im Newsbeitrag
news:1PQ0e.3481$gI5.1145@newsread1.news.pas.earthlink.net...
The LM324 model from TI works fine,but the one from National
Semiconductor is junk.
I tried numerous Analog Devices models for various rail-to-rail opamps,
and found that almost all i tried gave me the same kind of cryptic square
root error.
Those tried: AD8605, AD531, AD541, AD8552, and the AD8571; the only one
tried that did work was for the AD8614.
Now i would dearly like to have a set of models that were known to work
(and more or less correctly), but i need to get a working AD8605 model.
The sets i have came from the manufacturer created in the latter of
1992, and thus are not quite up-to-date.
However, the model for the AD8605 was downloaded via the web just
yesterday - implying the problem is not fixed.

Can anyone help?
Click to expand...
Hello Robert,
I don't believe that you really can judge the quality of these
models as a beginner with SPICE simulations.
I agree with you that most models have difficulties with convergence.
Many of them are really over complicated and sometimes generated
by stupid programs or "roboters" and not by engineers.

I assume that the listed models will work with some tweaking
of the convergence parameters.

What simulator do you use?
If it's LTspice then send me your files and I will make
you a working example with your AD8605.
I always want to see the schematic, because I know that
people sometimes have errors in their circuit.
One important thing is to have a DC path to ground(0).


Best Regards,
Helmut
Moderator of the LTspice user group
 
On Fri, 25 Mar 2005 09:26:21 GMT, Robert Baer
<robertbaer@earthlink.net> wrote:

The LM324 model from TI works fine,but the one from National
Semiconductor is junk.
I tried numerous Analog Devices models for various rail-to-rail
opamps, and found that almost all i tried gave me the same kind of
cryptic square root error.
Those tried: AD8605, AD531, AD541, AD8552, and the AD8571; the only
one tried that did work was for the AD8614.
Now i would dearly like to have a set of models that were known to
work (and more or less correctly), but i need to get a working AD8605 model.
The sets i have came from the manufacturer created in the latter of
1992, and thus are not quite up-to-date.
However, the model for the AD8605 was downloaded via the web just
yesterday - implying the problem is not fixed.

Can anyone help?
Click to expand...
Problem noted, and forwarded to the appropriate device-modeling
manager at Analog Devices.

I, personally, have experienced some problems with ADI models.
Reported same, and was told, "They work just fine here."

So don't hold your breath.

BTW, Sennewald is wrong when he says, "...generated by stupid programs
or "roboters" and not by engineers."

They ARE generated by engineers, or should I say it as "engineers"
?:)

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.
 
----- Original Message -----
From: "Jim Thompson" <thegreatone@example.com>
Newsgroups: sci.electronics.cad
Sent: Friday, March 25, 2005 3:37 PM
Subject: Re: Problems with SPICE models from vendors


On Fri, 25 Mar 2005 09:26:21 GMT, Robert Baer
robertbaer@earthlink.net> wrote:

The LM324 model from TI works fine,but the one from National
Semiconductor is junk.
I tried numerous Analog Devices models for various rail-to-rail
opamps, and found that almost all i tried gave me the same kind of
cryptic square root error.
Those tried: AD8605, AD531, AD541, AD8552, and the AD8571; the only
one tried that did work was for the AD8614.
Now i would dearly like to have a set of models that were known to
work (and more or less correctly), but i need to get a working AD8605
model.
The sets i have came from the manufacturer created in the latter of
1992, and thus are not quite up-to-date.
However, the model for the AD8605 was downloaded via the web just
yesterday - implying the problem is not fixed.

Can anyone help?

Problem noted, and forwarded to the appropriate device-modeling
manager at Analog Devices.
Click to expand...
Hello Jim,
this wasn't necessary. This AD8605 model runs without any
convergence problem in LTspice. So the model doesn't have any error.
Yuu should withdraw your email to AD and apologize to the manager
you have contacted for any inconvenience. :)

Best Regards,
Helmut
 
On Fri, 25 Mar 2005 16:00:04 +0100, "Helmut Sennewald"
<helmutsennewald@t-online.de> wrote:

----- Original Message -----
From: "Jim Thompson" <thegreatone@example.com
Newsgroups: sci.electronics.cad
Sent: Friday, March 25, 2005 3:37 PM
Subject: Re: Problems with SPICE models from vendors


On Fri, 25 Mar 2005 09:26:21 GMT, Robert Baer
robertbaer@earthlink.net> wrote:

The LM324 model from TI works fine,but the one from National
Semiconductor is junk.
I tried numerous Analog Devices models for various rail-to-rail
opamps, and found that almost all i tried gave me the same kind of
cryptic square root error.
Those tried: AD8605, AD531, AD541, AD8552, and the AD8571; the only
one tried that did work was for the AD8614.
Now i would dearly like to have a set of models that were known to
work (and more or less correctly), but i need to get a working AD8605
model.
The sets i have came from the manufacturer created in the latter of
1992, and thus are not quite up-to-date.
However, the model for the AD8605 was downloaded via the web just
yesterday - implying the problem is not fixed.

Can anyone help?

Problem noted, and forwarded to the appropriate device-modeling
manager at Analog Devices.

Hello Jim,
this wasn't necessary. This AD8605 model runs without any
convergence problem in LTspice. So the model doesn't have any error.
Yuu should withdraw your email to AD and apologize to the manager
you have contacted for any inconvenience. :)

Best Regards,
Helmut
Click to expand...
I simply passed on the posting to the ADI manager.

As previously noted, I, personally, have experienced issues with ADI
models.

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.
 
On Fri, 25 Mar 2005 09:03:04 -0700, Jim Thompson
<thegreatone@example.com> wrote:

On Fri, 25 Mar 2005 16:00:04 +0100, "Helmut Sennewald"
helmutsennewald@t-online.de> wrote:

----- Original Message -----
From: "Jim Thompson" <thegreatone@example.com
Newsgroups: sci.electronics.cad
Sent: Friday, March 25, 2005 3:37 PM
Subject: Re: Problems with SPICE models from vendors


On Fri, 25 Mar 2005 09:26:21 GMT, Robert Baer
robertbaer@earthlink.net> wrote:

The LM324 model from TI works fine,but the one from National
Semiconductor is junk.
I tried numerous Analog Devices models for various rail-to-rail
opamps, and found that almost all i tried gave me the same kind of
cryptic square root error.
Those tried: AD8605, AD531, AD541, AD8552, and the AD8571; the only
one tried that did work was for the AD8614.
Now i would dearly like to have a set of models that were known to
work (and more or less correctly), but i need to get a working AD8605
model.
The sets i have came from the manufacturer created in the latter of
1992, and thus are not quite up-to-date.
However, the model for the AD8605 was downloaded via the web just
yesterday - implying the problem is not fixed.

Can anyone help?

Problem noted, and forwarded to the appropriate device-modeling
manager at Analog Devices.

Hello Jim,
this wasn't necessary. This AD8605 model runs without any
convergence problem in LTspice. So the model doesn't have any error.
Yuu should withdraw your email to AD and apologize to the manager
you have contacted for any inconvenience. :)

Best Regards,
Helmut


I simply passed on the posting to the ADI manager.

As previously noted, I, personally, have experienced issues with ADI
models.

...Jim Thompson
Click to expand...
But the AD8605 seems to NOT be one of them. Works AOK on PSpice.

Results conveyed to JA at ADI.

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.
 
<zineddine.zidane@gmail.com> schrieb im Newsbeitrag
news:1111772454.985113.86850@l41g2000cwc.googlegroups.com...
hello folks, just saw your message about my Spice models. I did the
AD8605 model and would like to know what it is that you think isn't
working. I would prefer to see the test circuit you're using and
understand what you're trying to do. And if it really doesn't work,
then I owe you a pizza of your choice.
Click to expand...
Good morning Sir,
I posted 2h40m ago that this model has no problem.
Have you overlooked that or do you do you see postings only
after many hours? Please use a better news reader.
May news reader is uptodate within minutes.

Best Regards,
Helmut



My posting from 2h40m ago:

Problem noted, and forwarded to the appropriate device-modeling
manager at Analog Devices.
Click to expand...
Hello Jim,
this wasn't necessary. This AD8605 model runs without any
convergence problem in LTspice. So the model doesn't have any error.
Yuu should withdraw your email to AD and apologize to the manager
you have contacted for any inconvenience. :)

Best Regards,
Helmut
 
On Fri, 25 Mar 2005 19:44:15 +0100, "Helmut Sennewald"
<HelmutSennewald@t-online.de> wrote:

zineddine.zidane@gmail.com> schrieb im Newsbeitrag
news:1111772454.985113.86850@l41g2000cwc.googlegroups.com...
hello folks, just saw your message about my Spice models. I did the
AD8605 model and would like to know what it is that you think isn't
working. I would prefer to see the test circuit you're using and
understand what you're trying to do. And if it really doesn't work,
then I owe you a pizza of your choice.

Good morning Sir,
I posted 2h40m ago that this model has no problem.
Have you overlooked that or do you do you see postings only
after many hours? Please use a better news reader.
May news reader is uptodate within minutes.

Best Regards,
Helmut



My posting from 2h40m ago:

Problem noted, and forwarded to the appropriate device-modeling
manager at Analog Devices.

Hello Jim,
this wasn't necessary. This AD8605 model runs without any
convergence problem in LTspice. So the model doesn't have any error.
Yuu should withdraw your email to AD and apologize to the manager
you have contacted for any inconvenience. :)

Best Regards,
Helmut
Click to expand...
I have also checked it independently myself, on PSpice v10.3.

NO PROBLEM!

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.
 
Helmut Sennewald wrote:
"Robert Baer" <robertbaer@earthlink.net> schrieb im Newsbeitrag
news:1PQ0e.3481$gI5.1145@newsread1.news.pas.earthlink.net...

The LM324 model from TI works fine,but the one from National
Semiconductor is junk.
I tried numerous Analog Devices models for various rail-to-rail opamps,
and found that almost all i tried gave me the same kind of cryptic square
root error.
Those tried: AD8605, AD531, AD541, AD8552, and the AD8571; the only one
tried that did work was for the AD8614.
Now i would dearly like to have a set of models that were known to work
(and more or less correctly), but i need to get a working AD8605 model.
The sets i have came from the manufacturer created in the latter of
1992, and thus are not quite up-to-date.
However, the model for the AD8605 was downloaded via the web just
yesterday - implying the problem is not fixed.

Can anyone help?


Hello Robert,
I don't believe that you really can judge the quality of these
models as a beginner with SPICE simulations.
I agree with you that most models have difficulties with convergence.
Many of them are really over complicated and sometimes generated
by stupid programs or "roboters" and not by engineers.

I assume that the listed models will work with some tweaking
of the convergence parameters.

What simulator do you use?
If it's LTspice then send me your files and I will make
you a working example with your AD8605.
I always want to see the schematic, because I know that
people sometimes have errors in their circuit.
One important thing is to have a DC path to ground(0).


Best Regards,
Helmut
Moderator of the LTspice user group




Well, in a sense you are correct in labellling be as a beginner; i
Click to expand...
rarely use SPICE, but that useage has covered over 30 years.
When one models a simple voltage follower, with the NI input half way
between the poser supplies for the op-amp, one expects it to work, and
not give a cryptic square root error.
Furthermore, replacing the model used to a different one (eg replace
the call from the AD8605 to the AD8614 (and changing *nothing* else) and
have it work begs the question: what is wrong with the AD8605 model?
The same can be said about the models for the LM324; the TI model
works and the NatSemi does not.

And speaking of bad models that DO "work", the AD8614 is rather poor
(from the .OUT file):

.OPTIONS ACCT LIST NODE OPTS NUMDGT=6 RELTOL=0.00001 NOPAGE
.TEMP 27
.LIB ANLG_DEV.LIB ; most rail-to-rail opamps die with error
.DC VBAT 4.499 4.501 0.001
VBAT 01 00 DC 4.5
VSET 10 00 0.209171
VIN 05 00 0.018051
R2 05 07 18.4K
R3 10 08 18.4K
R4 09 07 100K
* NI I OUT
XAMP2 08 07 01 00 09 AD8614/AD
.PRINT DC V(05) V(07) V(08) V(09)
.PLOT DC V(05) V(07) V(08) V(09)
.SAVE

V(5) V(7) V(8) V(9)

1.80510E-02 2.22746E-01 2.21746E-01 1.26487E+00

Look at the poor results: large input currents, large Vos. Almost
useless; certainly not representative of the part.
 
Jim Thompson wrote:

On Fri, 25 Mar 2005 09:26:21 GMT, Robert Baer
robertbaer@earthlink.net> wrote:


The LM324 model from TI works fine,but the one from National
Semiconductor is junk.
I tried numerous Analog Devices models for various rail-to-rail
opamps, and found that almost all i tried gave me the same kind of
cryptic square root error.
Those tried: AD8605, AD531, AD541, AD8552, and the AD8571; the only
one tried that did work was for the AD8614.
Now i would dearly like to have a set of models that were known to
work (and more or less correctly), but i need to get a working AD8605 model.
The sets i have came from the manufacturer created in the latter of
1992, and thus are not quite up-to-date.
However, the model for the AD8605 was downloaded via the web just
yesterday - implying the problem is not fixed.

Can anyone help?


Problem noted, and forwarded to the appropriate device-modeling
manager at Analog Devices.

I, personally, have experienced some problems with ADI models.
Reported same, and was told, "They work just fine here."

So don't hold your breath.

BTW, Sennewald is wrong when he says, "...generated by stupid programs
or "roboters" and not by engineers."

They ARE generated by engineers, or should I say it as "engineers"
?:)

...Jim Thompson
I appreciate that you passed on the comments.
Click to expand...
Please see my slightly earlier response, showing problems with the
AD8614 (high input currents and high Vos).
 
Helmut Sennewald wrote:

----- Original Message -----
From: "Jim Thompson" <thegreatone@example.com
Newsgroups: sci.electronics.cad
Sent: Friday, March 25, 2005 3:37 PM
Subject: Re: Problems with SPICE models from vendors



On Fri, 25 Mar 2005 09:26:21 GMT, Robert Baer
robertbaer@earthlink.net> wrote:


The LM324 model from TI works fine,but the one from National
Semiconductor is junk.
I tried numerous Analog Devices models for various rail-to-rail
opamps, and found that almost all i tried gave me the same kind of
cryptic square root error.
Those tried: AD8605, AD531, AD541, AD8552, and the AD8571; the only
one tried that did work was for the AD8614.
Now i would dearly like to have a set of models that were known to
work (and more or less correctly), but i need to get a working AD8605
model.
The sets i have came from the manufacturer created in the latter of
1992, and thus are not quite up-to-date.
However, the model for the AD8605 was downloaded via the web just
yesterday - implying the problem is not fixed.

Can anyone help?

Problem noted, and forwarded to the appropriate device-modeling
manager at Analog Devices.


Hello Jim,
this wasn't necessary. This AD8605 model runs without any
convergence problem in LTspice. So the model doesn't have any error.
Yuu should withdraw your email to AD and apologize to the manager
you have contacted for any inconvenience. :)

Best Regards,
Helmut


Please tell me why it does not work (and others mentioned) and that
Click to expand...
the model for the AD8614 does work.
I am using a DOS version of TopSpice.
And look at an earlier posting where i clearly show that the AD8614
model gives large input currents and a large Vos.
 
zineddine.zidane@gmail.com wrote:

hello folks, just saw your message about my Spice models. I did the
AD8605 model and would like to know what it is that you think isn't
working. I would prefer to see the test circuit you're using and
understand what you're trying to do. And if it really doesn't work,
then I owe you a pizza of your choice.






Helmut Sennewald wrote:

"Robert Baer" <robertbaer@earthlink.net> schrieb im Newsbeitrag
news:1PQ0e.3481$gI5.1145@newsread1.news.pas.earthlink.net...

The LM324 model from TI works fine,but the one from National
Semiconductor is junk.
I tried numerous Analog Devices models for various rail-to-rail

opamps,

and found that almost all i tried gave me the same kind of cryptic

square

root error.
Those tried: AD8605, AD531, AD541, AD8552, and the AD8571; the

only one

tried that did work was for the AD8614.
Now i would dearly like to have a set of models that were known

to work

(and more or less correctly), but i need to get a working AD8605

model.

The sets i have came from the manufacturer created in the latter

of

1992, and thus are not quite up-to-date.
However, the model for the AD8605 was downloaded via the web just


yesterday - implying the problem is not fixed.

Can anyone help?

Hello Robert,
I don't believe that you really can judge the quality of these
models as a beginner with SPICE simulations.
I agree with you that most models have difficulties with convergence.
Many of them are really over complicated and sometimes generated
by stupid programs or "roboters" and not by engineers.

I assume that the listed models will work with some tweaking
of the convergence parameters.

What simulator do you use?
If it's LTspice then send me your files and I will make
you a working example with your AD8605.
I always want to see the schematic, because I know that
people sometimes have errors in their circuit.
One important thing is to have a DC path to ground(0).


Best Regards,
Helmut
Moderator of the LTspice user group


Here is a partial of the .OUT for the AD8614 which "works":
Click to expand...
.OPTIONS ACCT LIST NODE OPTS NUMDGT=6 RELTOL=0.00001 NOPAGE
.TEMP 27
.LIB ANLG_DEV.LIB ; most rail-to-rail opamps die with square
root error
.DC VBAT 4.499 4.501 0.001
VBAT 01 00 DC 4.5
VSET 10 00 0.209171
VIN 05 00 0.018051
R2 05 07 18.4K
R3 10 08 18.4K
R4 09 07 100K
* NI I OUT
XAMP2 08 07 01 00 09 AD8614/AD ;AD8605 U2
.PRINT DC V(05) V(07) V(08) V(09)
.PLOT DC V(05) V(07) V(08) V(09)
.SAVE

V(5) V(7) V(8) V(9)

1.80510E-02 2.22746E-01 2.21746E-01 1.26487E+00

Note the large input currents and large Vos.
Will see if i can run my DOS TopSpice when online...
***********
Well, the error message is only on the screen, and it is hard to read.
If i interpreted it correctly, it states "run time error M6201: MATH
-sqrt: DOMAIN error".
I hope this information is of some use.
Meanwhile, maybe i can figure out how to download LTspice (if it is
not gigantic, as i am on POTS).

***********
 
On Fri, 25 Mar 2005 22:38:18 GMT, Robert Baer
<robertbaer@earthlink.net> wrote:

Helmut Sennewald wrote:
"Robert Baer" <robertbaer@earthlink.net> schrieb im Newsbeitrag
news:1PQ0e.3481$gI5.1145@newsread1.news.pas.earthlink.net...

The LM324 model from TI works fine,but the one from National
Semiconductor is junk.
I tried numerous Analog Devices models for various rail-to-rail opamps,
and found that almost all i tried gave me the same kind of cryptic square
root error.
Those tried: AD8605, AD531, AD541, AD8552, and the AD8571; the only one
tried that did work was for the AD8614.
Now i would dearly like to have a set of models that were known to work
(and more or less correctly), but i need to get a working AD8605 model.
The sets i have came from the manufacturer created in the latter of
1992, and thus are not quite up-to-date.
However, the model for the AD8605 was downloaded via the web just
yesterday - implying the problem is not fixed.

Can anyone help?


Hello Robert,
I don't believe that you really can judge the quality of these
models as a beginner with SPICE simulations.
I agree with you that most models have difficulties with convergence.
Many of them are really over complicated and sometimes generated
by stupid programs or "roboters" and not by engineers.

I assume that the listed models will work with some tweaking
of the convergence parameters.

What simulator do you use?
If it's LTspice then send me your files and I will make
you a working example with your AD8605.
I always want to see the schematic, because I know that
people sometimes have errors in their circuit.
One important thing is to have a DC path to ground(0).


Best Regards,
Helmut
Moderator of the LTspice user group




Well, in a sense you are correct in labellling be as a beginner; i
rarely use SPICE, but that useage has covered over 30 years.
When one models a simple voltage follower, with the NI input half way
between the poser supplies for the op-amp, one expects it to work, and
not give a cryptic square root error.
Furthermore, replacing the model used to a different one (eg replace
the call from the AD8605 to the AD8614 (and changing *nothing* else) and
have it work begs the question: what is wrong with the AD8605 model?
The same can be said about the models for the LM324; the TI model
works and the NatSemi does not.

And speaking of bad models that DO "work", the AD8614 is rather poor
(from the .OUT file):

.OPTIONS ACCT LIST NODE OPTS NUMDGT=6 RELTOL=0.00001 NOPAGE
.TEMP 27
.LIB ANLG_DEV.LIB ; most rail-to-rail opamps die with error
.DC VBAT 4.499 4.501 0.001
VBAT 01 00 DC 4.5
VSET 10 00 0.209171
VIN 05 00 0.018051
R2 05 07 18.4K
R3 10 08 18.4K
R4 09 07 100K
* NI I OUT
XAMP2 08 07 01 00 09 AD8614/AD
.PRINT DC V(05) V(07) V(08) V(09)
.PLOT DC V(05) V(07) V(08) V(09)
.SAVE

V(5) V(7) V(8) V(9)

1.80510E-02 2.22746E-01 2.21746E-01 1.26487E+00

Look at the poor results: large input currents, large Vos. Almost
useless; certainly not representative of the part.
Click to expand...
For the rated VCC (+5V and up), I'm getting offset right at the
typical of 1mV.

BUT the IB's are about double the MAX spec.

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.
 
On 25 Mar 2005 15:25:44 -0800, zineddine.zidane@gmail.com wrote:

Hmm useless huh? the AD8614 has 1mV of Vos and the model has 1mV, I
just looked at it, so I don't know what you mean by not working. I
think you may be overlooking some things here. Here's the Vos in the
netlist...
EOS 7 1 POLY(2) (73,98) (81,98) 1E-3 1 1


[snip]
Click to expand...

I just verified Baer's setup with PSpice. The IB's are running
~700nA, substantially larger than the MAX spec.

I simply visually scanned the data sheet, so I don't know... are we
close enough to negative rail to cause the high IB?

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.
 
"Robert Baer" <robertbaer@earthlink.net> schrieb im Newsbeitrag
news:%v01e.3960$gI5.2228@newsread1.news.pas.earthlink.net...
Helmut Sennewald wrote:

----- Original Message -----
From: "Jim Thompson" <thegreatone@example.com
Newsgroups: sci.electronics.cad
Sent: Friday, March 25, 2005 3:37 PM
Subject: Re: Problems with SPICE models from vendors



On Fri, 25 Mar 2005 09:26:21 GMT, Robert Baer
robertbaer@earthlink.net> wrote:


The LM324 model from TI works fine,but the one from National
Semiconductor is junk.
I tried numerous Analog Devices models for various rail-to-rail
opamps, and found that almost all i tried gave me the same kind of
cryptic square root error.
Those tried: AD8605, AD531, AD541, AD8552, and the AD8571; the only
one tried that did work was for the AD8614.
Now i would dearly like to have a set of models that were known to
work (and more or less correctly), but i need to get a working AD8605
model.
The sets i have came from the manufacturer created in the latter of
1992, and thus are not quite up-to-date.
However, the model for the AD8605 was downloaded via the web just
yesterday - implying the problem is not fixed.

Can anyone help?

Problem noted, and forwarded to the appropriate device-modeling
manager at Analog Devices.


Hello Jim,
this wasn't necessary. This AD8605 model runs without any
convergence problem in LTspice. So the model doesn't have any error.
Yuu should withdraw your email to AD and apologize to the manager
you have contacted for any inconvenience. :)

Best Regards,
Helmut
Please tell me why it does not work (and others mentioned) and that the
model for the AD8614 does work.
I am using a DOS version of TopSpice.
And look at an earlier posting where i clearly show that the AD8614
model gives large input currents and a large Vos.
Click to expand...
Hello Robert,
please tell me who said that the Ad8605 model doesn't work?
Maybe TopSpice has problems with this opamp whereas other SPICE
variants don't have a problem with the AD8605.
The different SPICE versions on the market are far off from the
original SPICE program code.

Best Regards,
Helmut
 
Helmut Sennewald wrote:

"Robert Baer" <robertbaer@earthlink.net> schrieb im Newsbeitrag
news:%v01e.3960$gI5.2228@newsread1.news.pas.earthlink.net...

Helmut Sennewald wrote:


----- Original Message -----
From: "Jim Thompson" <thegreatone@example.com
Newsgroups: sci.electronics.cad
Sent: Friday, March 25, 2005 3:37 PM
Subject: Re: Problems with SPICE models from vendors




On Fri, 25 Mar 2005 09:26:21 GMT, Robert Baer
robertbaer@earthlink.net> wrote:



The LM324 model from TI works fine,but the one from National
Semiconductor is junk.
I tried numerous Analog Devices models for various rail-to-rail
opamps, and found that almost all i tried gave me the same kind of
cryptic square root error.
Those tried: AD8605, AD531, AD541, AD8552, and the AD8571; the only
one tried that did work was for the AD8614.
Now i would dearly like to have a set of models that were known to
work (and more or less correctly), but i need to get a working AD8605
model.
The sets i have came from the manufacturer created in the latter of
1992, and thus are not quite up-to-date.
However, the model for the AD8605 was downloaded via the web just
yesterday - implying the problem is not fixed.

Can anyone help?

Problem noted, and forwarded to the appropriate device-modeling
manager at Analog Devices.


Hello Jim,
this wasn't necessary. This AD8605 model runs without any
convergence problem in LTspice. So the model doesn't have any error.
Yuu should withdraw your email to AD and apologize to the manager
you have contacted for any inconvenience. :)

Best Regards,
Helmut

Please tell me why it does not work (and others mentioned) and that the
model for the AD8614 does work.
I am using a DOS version of TopSpice.
And look at an earlier posting where i clearly show that the AD8614
model gives large input currents and a large Vos.


Hello Robert,
please tell me who said that the Ad8605 model doesn't work?
Maybe TopSpice has problems with this opamp whereas other SPICE
variants don't have a problem with the AD8605.
The different SPICE versions on the market are far off from the
original SPICE program code.

Best Regards,
Helmut


I said that the AD8605 model does not work; at least for the old DOS
Click to expand...
TopSpice.
Based on raw experience.
Found the same model appears to work in Switchercad3 which i recently
downloaded.
See previous recent postings by me; there are nasty errors in a
simple amplifier circuit using the AD8605.
 
On Sat, 26 Mar 2005 03:56:11 GMT, Robert Baer
<robertbaer@earthlink.net> wrote:

zineddine.zidane@gmail.com wrote:

Hmm useless huh? the AD8614 has 1mV of Vos and the model has 1mV, I
just looked at it, so I don't know what you mean by not working. I
think you may be overlooking some things here. Here's the Vos in the
netlist...
EOS 7 1 POLY(2) (73,98) (81,98) 1E-3 1 1





Robert Baer wrote:

Helmut Sennewald wrote:

"Robert Baer" <robertbaer@earthlink.net> schrieb im Newsbeitrag
news:1PQ0e.3481$gI5.1145@newsread1.news.pas.earthlink.net...


The LM324 model from TI works fine,but the one from National
Semiconductor is junk.
I tried numerous Analog Devices models for various rail-to-rail

opamps,

and found that almost all i tried gave me the same kind of cryptic

square

root error.
Those tried: AD8605, AD531, AD541, AD8552, and the AD8571; the

only one

tried that did work was for the AD8614.
Now i would dearly like to have a set of models that were known

to work

(and more or less correctly), but i need to get a working AD8605

model.

The sets i have came from the manufacturer created in the latter

of

1992, and thus are not quite up-to-date.
However, the model for the AD8605 was downloaded via the web just


yesterday - implying the problem is not fixed.

Can anyone help?


Hello Robert,
I don't believe that you really can judge the quality of these
models as a beginner with SPICE simulations.
I agree with you that most models have difficulties with

convergence.

Many of them are really over complicated and sometimes generated
by stupid programs or "roboters" and not by engineers.

I assume that the listed models will work with some tweaking
of the convergence parameters.

What simulator do you use?
If it's LTspice then send me your files and I will make
you a working example with your AD8605.
I always want to see the schematic, because I know that
people sometimes have errors in their circuit.
One important thing is to have a DC path to ground(0).


Best Regards,
Helmut
Moderator of the LTspice user group





Well, in a sense you are correct in labellling be as a beginner; i


rarely use SPICE, but that useage has covered over 30 years.
When one models a simple voltage follower, with the NI input half

way

between the poser supplies for the op-amp, one expects it to work,

and

not give a cryptic square root error.
Furthermore, replacing the model used to a different one (eg

replace

the call from the AD8605 to the AD8614 (and changing *nothing* else)

and

have it work begs the question: what is wrong with the AD8605 model?
The same can be said about the models for the LM324; the TI model
works and the NatSemi does not.

And speaking of bad models that DO "work", the AD8614 is rather

poor

(from the .OUT file):

.OPTIONS ACCT LIST NODE OPTS NUMDGT=6 RELTOL=0.00001 NOPAGE
.TEMP 27
.LIB ANLG_DEV.LIB ; most rail-to-rail opamps die with error
.DC VBAT 4.499 4.501 0.001
VBAT 01 00 DC 4.5
VSET 10 00 0.209171
VIN 05 00 0.018051
R2 05 07 18.4K
R3 10 08 18.4K
R4 09 07 100K
* NI I OUT
XAMP2 08 07 01 00 09 AD8614/AD
.PRINT DC V(05) V(07) V(08) V(09)
.PLOT DC V(05) V(07) V(08) V(09)
.SAVE

V(5) V(7) V(8) V(9)

1.80510E-02 2.22746E-01 2.21746E-01 1.26487E+00

Look at the poor results: large input currents, large Vos. Almost


useless; certainly not representative of the part.


Ok, i am convinced that the AD8614 was a lousy choice - but it was
the only rail-to-rail model that worked at that time.
I have downloaded SwitcherCAD3 and have part of my circuit working
using the AD8605 model.
So it is clear that there is something about those
non-working-for-TopSpice models that goof it up, but is allowed in the
more modern SPICE programs.
That said, the results i get are WRONG - essentially it is saying
that 1+1 is not 2.
I could attach the .ASC file, but it is fairly large (about 4K), and
tell you what the node voltages SC3 gives.
Let me do it the quick way; SC3 sez:
N003 at 0.295mV; R2=18.2K from N003 to N007 at 0.188481V; op amp NI
at N006, I at N007, output at N008, V- at gnd, v+ at 4.5V; feedback
R4=100K from N006 to N007; N006 at 0.188571V; I(R2)=I(R4)=10.3399uA;
N008=0.376666V.

But do the calcs by hand; I(R2) = (0.188481V-0.000295V)/(18.2K) =
0.0103398mA. Drop across 100k then is 1.03398V; add to voltage at N007
for calc(N008)=1.222461V.

Therefore 1+1=2 and Spice is whistling Dixie.
Click to expand...
What I found disturbing was that the bias currents were way in excess
of MAX specification.

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.
 
Robert Baer wrote:

The LM324 model from TI works fine,but the one from National
Semiconductor is junk.
I tried numerous Analog Devices models for various rail-to-rail
opamps, and found that almost all i tried gave me the same kind of
cryptic square root error.
Those tried: AD8605, AD531, AD541, AD8552, and the AD8571; the only
one tried that did work was for the AD8614.
Now i would dearly like to have a set of models that were known to
work (and more or less correctly), but i need to get a working AD8605
model.
The sets i have came from the manufacturer created in the latter of
1992, and thus are not quite up-to-date.
However, the model for the AD8605 was downloaded via the web just
yesterday - implying the problem is not fixed.

Can anyone help?
Thanks!
Click to expand...
Using LTspice solved the problem.
It also ensures that the model accurately mirrors the schematic.
With the DOS TopSpice, transcription errors can cause problems (and
did!).
However, it *would* be of great use if:
1) one could easily edit wires (length, placement, number of corners and
where corners are).
2) one could have a little window by a (chosen) node that gave the DC
(or other value).
3) that the output, both text and graph could be directly saved. .PRINT
and .SAVE just do not cut it here.
4) that the duplicate function would allow creation of more than one;
sometimes you need 5 more of something...
*************
I noticed that in some cases, setting ITL1 and/or ITL6 "small" can
allow something to converge, where a setting of 200 or more can kill
convergence.
And he higher the value of ITL1 and/or ITL6, the worse the problem is.
Why??
 
In article <ltp1e.5675$H06.1598@newsread3.news.pas.earthlink.net>,
Robert Baer <robertbaer@earthlink.net> wrote:

Using LTspice solved the problem.

However, it *would* be of great use if:
[snip]
Click to expand...

Just to add to the LTspice wish-list........

An automatic cross-reference between opamp and
comparator part numbers and LT's own devices.

eg, select "TL081" from the list, but get given
the nearest LT device..... LTxxxx if an exact
pin for pin equivalent, (LTxxxx) if it is a
nearly but not quite equivalent.

If given the part numbers I don't mind calling
up LT devices as 'payment' for LTspice.

--
Tony Williams.
 
Tony Williams wrote:
In article <ltp1e.5675$H06.1598@newsread3.news.pas.earthlink.net>,
Robert Baer <robertbaer@earthlink.net> wrote:

Using LTspice solved the problem.

However, it *would* be of great use if:
[snip]

Just to add to the LTspice wish-list........

An automatic cross-reference between opamp and
comparator part numbers and LT's own devices.

eg, select "TL081" from the list, but get given
the nearest LT device..... LTxxxx if an exact
pin for pin equivalent, (LTxxxx) if it is a
nearly but not quite equivalent.
Click to expand...

I suppose you want the moon on a stick as well.

Kevin Aylward
informationEXTRACT@anasoft.co.uk
http://www.anasoft.co.uk
SuperSpice, a very affordable Mixed-Mode
Windows Simulator with Schematic Capture,
Waveform Display, FFT's and Filter Design.
 
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