Question on LT Spice equivalents...

[Chris Carlen]

Chaos Master wrote:

iscrivinhated/wrotou na
mensage/messagem <ppf020dae84oqcflcsp9ltcelvfnrrinu4@4ax.com> no grupo de
newstícias sci.electronics.cad a exatos Wed, 04 Feb 2004 00:44:54 +0000 :


Hi,

I need LT spice models for the TC7SU04F and 74HC04. However I imagine
Linear make their own generic equivalents of these popular ICs under
different designations. Either would suffice, I guess. Does anyone
know where they might be obtainable from? I've searched Linear's site
but without knowing which of their LT.series of chips are the same as
the above, I'm somewhat in the dark..


Linear makes only _analog_ IC's, I think. 74HCxx are digital.

I also heard that Analog makes only linear ICs.


:-D


--
____________________________________
Christopher R. Carlen
Principal Laser/Optical Technologist
Sandia National Laboratories CA USA
crcarle@sandia.gov

 

[Winfield Hill]

Paul Burridge wrote...

Winfield Hill wrote:

Paul, if you examine Toshiba's TC7SU04 datasheet and
the datasheet of 'U04 ICs from other companies you'll
see they're all very similar, so you can use a generic
model with a name similar to 74HCU04. Single-gate ICs
are intended to have similar properties to a single
gate from a six-gate package. Also, spice models of
multi-element ICs model only one element.

Thanks, Win. It seems you're right. The 74HCx model
available on the yahoo groups site (by Helmut!) does
the trick very well indeed.

The Toshiba TC7SU04 is an *unbuffered* gate, so take care
not to use a buffered-gate model, like the HC04, for it.

Thanks,
- Win

whill_at_picovolt-dot-com

 

[Chris Carlen]

Ban wrote:

Paul Burridge wrote:

Hi,

I need LT spice models for the TC7SU04F and 74HC04. However I imagine
Linear make their own generic equivalents of these popular ICs under
different designations. Either would suffice, I guess. Does anyone
know where they might be obtainable from? I've searched Linear's site
but without knowing which of their LT.series of chips are the same as
the above, I'm somewhat in the dark..



Paul,
I have to agree with Genome and Thompson- your abilities in electronics are
not up to using a tool like Spice, and I'm afraid will never be. :-(
Most important is to learn the basics, not playing around with something you
do not understand. With this question you again reveal in an embarassing way
your ignorance.

What are you talking about? Since SPICE can be used to simulate the
simplest of circuits, such as a voltage source and a resistor, it can be
utilized as both a design tool and a learning tool by everyone involved
in electronics, starting with basic circuit analysis 101.

Paul may not know some stuff, but to extrapolate that to mean he can
never know something is absurd. How do you know anything at all about
Paul's inherent intellectual capability?

It would be far wiser to do this:

1. Encourage Paul to realize that SPICE must not be used as a
substitute for understanding. Thus, one should study the classical
paper and pencil circuit analysis theory and practice it well. That
way, one can avoid being led astray by simulator results.

2. Encourage Paul to build up on the bench plenty of test circuits of
the fundamental types studied in circuit analysis texts. Understand on
the bench, and simultaneously work them in SPICE. Understand the subtle
differences between SPICE and the test bench.

3. At this point, Paul can begin to use SPICE more as a test bench than
the real physical test bench, which often works out to be a more
expedient route to performing a wide variety of experiments on circuits,
that would otherwise be very time consuming on the bench. This
expedience can enable one to focus on the reasoning processes of design
and troubleshooting, rather than spending most of ones energy rewinding
coils, etc.

Both parts are inverters made in HCMOS technology. Fairchild pioneered many
of these, so go to their website, click on logic ICs, HC and models...and
you can request a model:
http://www.fairchildsemi.com/models/email_model_file.jsp?file=hc04tm0.inc

They offer 3 different models for every gate: fast, typical and slow.
You can already see, digital parts are not so easy to spice and it is
usually not needed, unless you use them in an analog way.
Since you might want to make an oscillator or linear amplifier with it, a
model will be handy. Read also the datasheet, have a look at the internal
circuitry and try to understand how it works.
For this you need to know how a transistor or in this case a MosFet is
working. Read it up in AoE. Do not skip these fundamentals.

Now we're moving in the right direction.

Indeed, it would be wise for Paul to learn to be patient and hack
through datasheets. I think Paul might think it is necessary to have
detailed SPICE models for parts, and doesn't realize when the model
needs to and doesn't need to account for varying degrees of subtlety in
device behavior.

So:

4. Paul should be told that in a vast number of cases, say 90% of the
time, the gist of circuit operation can be ascertained with simplified
models of components. Thus, the built in digital components of LT-SPICE
are adequate for likely 99% of Paul's needs, and the only missing link
is that Paul needs to read the datasheet to find the few relevant
parameters like input thresholds, delay times, rise/fall times, etc., to
instruct the SPICE models on how to reasonably approximate the behavior
of the real devices. Thus, an important aspect of design and
simulation, is having a feeling for exactly what level of accounting for
device subtleties is needed. Do I just want to prove a rough circuit
concept? Or do I want to account precisely for device limitations,
power dissipations, etc.?

Then Paul won't have to go on wild goose chases for the exact models for
things most of the time, since he can just make reasonable
approximations using datasheet parameters and generic models. The same
goes for op-amps, which in certain cases can be modeled just fine with
only a VCVS, depending on what you are trying to accomplish.


Good day!

--
____________________________________
Christopher R. Carlen
Principal Laser/Optical Technologist
Sandia National Laboratories CA USA
crcarle@sandia.gov

 

[Ban]

Chris Carlen wrote:

What are you talking about? Since SPICE can be used to simulate the
simplest of circuits, such as a voltage source and a resistor, it can
be utilized as both a design tool and a learning tool by everyone
involved in electronics, starting with basic circuit analysis 101.

Paul may not know some stuff, but to extrapolate that to mean he can
never know something is absurd. How do you know anything at all about
Paul's inherent intellectual capability?

It would be far wiser to do this:

1. Encourage Paul to realize that SPICE must not be used as a
substitute for understanding. Thus, one should study the classical
paper and pencil circuit analysis theory and practice it well. That
way, one can avoid being led astray by simulator results.

2. Encourage Paul to build up on the bench plenty of test circuits of
the fundamental types studied in circuit analysis texts. Understand
on the bench, and simultaneously work them in SPICE. Understand the
subtle differences between SPICE and the test bench.

3. At this point, Paul can begin to use SPICE more as a test bench
than the real physical test bench, which often works out to be a more
expedient route to performing a wide variety of experiments on
circuits, that would otherwise be very time consuming on the bench.
This expedience can enable one to focus on the reasoning processes of
design and troubleshooting, rather than spending most of ones energy
rewinding coils, etc.

Christopher R. Carlen

Yes Chris, see my other reply, but I get pissed when someone has to express
his political opinion with his signature. Really I feel I should have coined
even some stronger reaction. He was already reminded by Genome before, but
seems not to have understood...
So that was just for him.
I usually do not write these kind of comments, and I wouldn't have felt this
way, if we still had Robert, but sometimes It just comes through you.

Take it easy, and my apologies to everyone who feels offended...

ciao Ban

 

[Spehro Pefhany]

On Wed, 04 Feb 2004 17:01:35 GMT, the renowned "Ban" <bansuri@web.de>
wrote:

Yes Chris, see my other reply, but I get pissed when someone has to express
his political opinion with his signature. Really I feel I should have coined
even some stronger reaction. He was already reminded by Genome before, but
seems not to have understood...
So that was just for him.
I usually do not write these kind of comments, and I wouldn't have felt this
way, if we still had Robert, but sometimes It just comes through you.

Take it easy, and my apologies to everyone who feels offended...

Your apology offends me.

Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

 

[Jim Thompson]

On Wed, 04 Feb 2004 17:01:35 GMT, "Ban" <bansuri@web.de> wrote:

Chris Carlen wrote:
[snip]
It would be far wiser to do this:

Encourage Paul to THINK.

[snip]

Yes Chris, see my other reply, but I get pissed when someone has to express
his political opinion with his signature. Really I feel I should have coined
even some stronger reaction. He was already reminded by Genome before, but
seems not to have understood...
So that was just for him.
I usually do not write these kind of comments, and I wouldn't have felt this
way, if we still had Robert, but sometimes It just comes through you.

Take it easy, and my apologies to everyone who feels offended...

ciao Ban

I'm not offended...

I get cranky and irritable every time I suggest pencil and paper, and
get adverse reactions. If lurkers can't manage pencil and paper
analyses they don't belong in circuit design, and should stop
pretending same.

...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.

 

[Syd Rumpo]

In message <Pz9Ub.188786$VW.7684378@news3.tin.it>, Ban <bansuri@web.de>
writes

I usually do not write these kind of comments, and I wouldn't have felt this
way, if we still had Robert, but sometimes It just comes through you.

But Robert/Fred's still alive and kicking, I'm happy to observe. Apart
from the content, you can tell by the dash- like this- with no leading
space.


--
Syd

 

[Winfield Hill]

Syd Rumpo wrote...

you can tell by the dash- like this- with no leading space.

Lots of people do that.

Thanks,
- Win

whill_at_picovolt-dot-com

 

[Winfield Hill]

Chris Carlen wrote...

What are you talking about? Since SPICE can be used to simulate the
simplest of circuits, such as a voltage source and a resistor, it can
be utilized as both a design tool and a learning tool by everyone
involved in electronics, starting with basic circuit analysis 101.

The problem with this is the poor folks begin to think what spice
tells them must be right. I mean, they get answers to six-digits,
how can that be wrong? So we see a statement like, "I tested the
circuit," when really should have said, "I ran a spice simulation."

Meanwhile they're using the wrong model, or poorly-designed models,
or mis-using the model, and have failed to add any necessary real-
world parasitic elements, like an actual bench circuit will have.
Furthermore, they run the model with a fixed supply voltage with
zero-ohms impedance, and at the default temperature. Of course
they fail to test for any effects due to component tolerances.
Although the results may have little relation to reality, they go
forth with great confidence they've designed and tested a circuit.

In the case of basic circuit analysis 101, they use inductors with
no internal resistance or self capacitance, and have no idea what
magnetic saturation, eddy currents, or self-heating, or proximity-
effect losses are. In the end they learn just what the book taught,
once again, bearing little relation to the real world. <sigh>

Thanks,
- Win

whill_at_picovolt-dot-com

 

[Paul Burridge]

On 4 Feb 2004 07:50:39 -0800, Winfield Hill
<Winfield_member@newsguy.com> wrote:

The Toshiba TC7SU04 is an *unbuffered* gate, so take care
not to use a buffered-gate model, like the HC04, for it.

Well worth keeping in mind, I agree. Fortunately this application (the
active element in a c-mos oscillator) both seem to work equally well,
certainly when breadboarded.
Here's the circuit fragment:


Inverter

|\
o----|->O--------o
| |/ |
| |
| |
| 500k |
| ___ |
+----|___|-------+
| |
| |
| |
| .-.
| 8Mhz | |1.5k
| ceramic | |
| resonator '-'
| _ | GND
| || || |
+------|| ||-----+
| ||_|| |
| |
| |
--- ---
5pF --- 5pF ---
| |

GND GND
created by Andy´s ASCII-Circuit v1.24.140803 Beta www.tech-chat.de


By reducing the twin capacitances to undesirably low levels and by the
insertion of a suitable inductor (0.05mH) in series with the
resonator, I can *just* get the output up to 8.15Mhz. Pity as I could
really use 8.2Mhz. Any ideas how I can squeeze another 50Khz out of
it?

p.

--

The BBC: Licensed at public expense to spread lies.

 

[Jim Thompson]

On 4 Feb 2004 11:08:28 -0800, Winfield Hill
<Winfield_member@newsguy.com> wrote:

[snip]

In the end they learn just what the book taught,
once again, bearing little relation to the real world. <sigh

Thanks,
- Win

whill_at_picovolt-dot-com

But they get paid $10/hour ;-)

...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.

 

[Winfield Hill]

Jim Thompson wrote...

But they get paid $10/hour ;-)

Indeed. I guess they're many reasons we get paid
the big bucks! :&gt

Thanks,
- Win

whill_at_picovolt-dot-com

 

[Stefan Heinzmann]

Paul Burridge wrote:

On 4 Feb 2004 07:50:39 -0800, Winfield Hill
Winfield_member@newsguy.com> wrote:


The Toshiba TC7SU04 is an *unbuffered* gate, so take care
not to use a buffered-gate model, like the HC04, for it.


Well worth keeping in mind, I agree. Fortunately this application (the
active element in a c-mos oscillator) both seem to work equally well,
certainly when breadboarded.
Here's the circuit fragment:


Inverter

|\
o----|->O--------o
| |/ |
| |
| |
| 500k |
| ___ |
+----|___|-------+
| |
| |
| |
| .-.
| 8Mhz | |1.5k
| ceramic | |
| resonator '-'
| _ | GND
| || || |
+------|| ||-----+
| ||_|| |
| |
| |
--- ---
5pF --- 5pF ---
| |

GND GND
created by Andy´s ASCII-Circuit v1.24.140803 Beta www.tech-chat.de


By reducing the twin capacitances to undesirably low levels and by the
insertion of a suitable inductor (0.05mH) in series with the
resonator, I can *just* get the output up to 8.15Mhz. Pity as I could
really use 8.2Mhz. Any ideas how I can squeeze another 50Khz out of
it?

Crystals can typically only be "pulled" away about 0.1% from their
nominal frequency. Resonators somewhat more (I don't know how much).
What you're attempting is asking a bit much. I am surprised that you can
even get as far as 8.15MHz. If you want 8.2MHz you should buy a
corresponding resonator.

--
Cheers
Stefan

 

[Syd Rumpo]

In message <bvret7012ke@drn.newsguy.com>, Winfield Hill
<Winfield_member@newsguy.com> writes

Syd Rumpo wrote...

you can tell by the dash- like this- with no leading space.

Lots of people do that.

Well, I can think of 'two' anyway


--
Syd

 

[Chris Carlen]

Winfield Hill wrote:

Chris Carlen wrote...

What are you talking about? Since SPICE can be used to simulate the
simplest of circuits, such as a voltage source and a resistor, it can
be utilized as both a design tool and a learning tool by everyone
involved in electronics, starting with basic circuit analysis 101.


The problem with this is the poor folks begin to think what spice
tells them must be right. I mean, they get answers to six-digits,
how can that be wrong? So we see a statement like, "I tested the
circuit," when really should have said, "I ran a spice simulation."

Meanwhile they're using the wrong model, or poorly-designed models,
or mis-using the model, and have failed to add any necessary real-
world parasitic elements, like an actual bench circuit will have.
Furthermore, they run the model with a fixed supply voltage with
zero-ohms impedance, and at the default temperature. Of course
they fail to test for any effects due to component tolerances.
Although the results may have little relation to reality, they go
forth with great confidence they've designed and tested a circuit.

In the case of basic circuit analysis 101, they use inductors with
no internal resistance or self capacitance, and have no idea what
magnetic saturation, eddy currents, or self-heating, or proximity-
effect losses are. In the end they learn just what the book taught,
once again, bearing little relation to the real world. <sigh

Thanks,
- Win

Hi Win:

I would expect that astute students, especially those who have tinkered
with electronics before engaging in formal study, and even those who
have not but are serious about learning the subject at not just a
theoretical level but a practical one as well, would raise questions
during their study that point to these very issues. For instance, my
text on basic electric circuits goes into the effects of loading on
filters after presenting the basic filters. It doesn't take much to
realize once someone mentions the existance of internal resistance in
inductors and caps, and self-capacitance of inductors, non-linearities
of non-air cored coils, etc., that the real world situation is far more
complex than the basics. But the basics provide the necessary tools to
then begin to tackle the complexity. Any student having completed a
basic circuits class, and having been told verbally that an L is really
a (R+sL)||(1/sC) and a C is really an (R+1/sC+sL), and that if needed
even more levels of parasitics can be factored in, should be able to sit
down and write out what the circuit really looks like in the final
analysis. Faced with that pile of complexity, they can then begin to
grasp that there are times when this or that parasitic is relevant, and
other times it isn't.

Since most students will have labs with teachers and lab guides that
will be able to bring up the subjects of parasitics, etc., the students
should discover the important clues regarding the limitations of
idealized analysis during formal education. Of course, then that just
means a more detailed analysis. The road is a bit more rocky when one
forges a path alone. But the same effect can be realized. By filtering
through discussions on this group to which I never chimed in, I've
amassed a vast collection of tidbits, that slowly congeal into real
knowledge as I encounter design problems in which the theory must be
complemented by these bits of reality.

In my prior post, I tried to suggest a combination of experiences with
theory, the bench, and simulation as being necessary to get to the point
of being able to synthesize the various factoids into real productivity.

I also tried to make it clear that grounding (heh heh) in the basics of
pencil/paper analysis and bench experiments is the defense mechanism
against sheepishly believing a computer. The simulator and the bench
should complement one another for beginners. Heck, I am studying
Verilog right now, and I frequently burn the exercises into a real PLD
with real switches and LEDs, just to keep getting that feeling of the
real McCoy.

Of course, maybe I am being optimistic about students. I only know the
way I was in school, and now learning on my own. It isn't about doing
the assignment, it is about exploring all the questions that arise from
each assignment or factoid that leads to the development of maturity of
technical insight.

And once I got to that point with chemistry, I promptly got tired and
moved to electronics. ;-)

Win, I would be interested to here what you perceive to be the
statistics on how many students really go beyond the call of duty, and
how many just get by?

Good day!











--
____________________________________
Christopher R. Carlen
Principal Laser/Optical Technologist
Sandia National Laboratories CA USA
crcarle@sandia.gov

 

[Jim Thompson]

On 4 Feb 2004 11:57:54 -0800, Winfield Hill
<Winfield_member@newsguy.com> wrote:

Jim Thompson wrote...

But they get paid $10/hour ;-)

Indeed. I guess they're many reasons we get paid
the big bucks! :&gt

Thanks,
- Win

whill_at_picovolt-dot-com

A lot of the whiners here remind me of most of the clowns I met when I
was a Mensa member... they expect to be paid the big bucks because
they are "smart", never mind productivity.

They have no idea of the amount of effort it takes to reach the status
of top-notch designer. And they certainly don't have the stamina to
handle the workload that I do.

And, to boot, I can drink them under the table ;-)

...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.

 

[Chris Carlen]

Jim Thompson wrote:

I get cranky and irritable every time I suggest pencil and paper, and
get adverse reactions. If lurkers can't manage pencil and paper
analyses they don't belong in circuit design, and should stop
pretending same.

...Jim Thompson

Well you know how much I love analysis, so I agree quite a bit.


Godd day!


--
____________________________________
Christopher R. Carlen
Principal Laser/Optical Technologist
Sandia National Laboratories CA USA
crcarle@sandia.gov

 

[Chaos Master]

Chaos Master[spam.is.deadly@hotmail.com] iscrivinhated/wrotou na mensage/messagem
<MPG.1a8a4cbb4358d86b989946@news.cis.dfn.de> no grupo de newstícias
sci.electronics.cad a exatos Wed, 4 Feb 2004 00:27:16 -0200 :

iscrivinhated/wrotou na
mensage/messagem <ppf020dae84oqcflcsp9ltcelvfnrrinu4@4ax.com> no grupo de
newstícias sci.electronics.cad a exatos Wed, 04 Feb 2004 00:44:54 +0000 :


Hi,

I need LT spice models for the TC7SU04F and 74HC04. However I imagine
Linear make their own generic equivalents of these popular ICs under
different designations. Either would suffice, I guess. Does anyone
know where they might be obtainable from? I've searched Linear's site
but without knowing which of their LT.series of chips are the same as
the above, I'm somewhat in the dark..

Linear makes only _analog_ IC's, I think. 74HCxx are digital.

PS: you can find those models at LTSpice' Yahoo! Groups list.
http://groups.yahoo.com/groups/LTSpice/ . You need to subscribe to the list,
however.



--
ChaosŽ - posting from Brazil
wizard_of_yendor.666@hotmail.com
remove the number of the beast - 666

 

[Spehro Pefhany]

On Wed, 04 Feb 2004 13:52:56 -0800, the renowned Chris Carlen
<crcarle@BOGUS.sandia.gov> wrote:

<big snip>

Win, I would be interested to here what you perceive to be the
statistics on how many students really go beyond the call of duty, and
how many just get by?

The Pareto distribution?

Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

 

[Max Hauser]

It's remarkable (and archivable) that a question such as
(in newspf020dae84oqcflcsp9ltcelvfnrrinu4@4ax.com )

Hi,

I need LT spice models for the TC7SU04F and 74HC04.

elicits responses such as

Give us a break! The reason he wants a SPICE model is because
HE CANNOT READ A DATASHEET! It's ridiculous to respond with
a real answer, he doesn't rate it.

and

I have to agree with Genome and Thompson- your abilities in
electronics are not up to using a tool like Spice, and I'm afraid will
never be. :-( Most important is to learn the basics, not playing
around with something you do not understand. With this question
you again reveal in an embarassing way your ignorance.

Now I admit that I don't know all the history that may lie behind this but
the exchange does paint a picture by itself. But to Mr Bloggs, who wrote

USENET is another failure, much like television with its early promise
of providing easily accessed educational and cultural resource, and its
degeneration into worthless trash content, USENET has also degenerated.

-- I'm unsure of the frame of reference for "degenerated.". (It could be
the famous 1983-84 exodus when serious users departed for list-servers
because of all of the new students signing on, or the general crowding by
the early 90s, or the "Eternal September" after the new pointy-clicky
Internet finally discovered the newsgroups.) The responses above are less
helpful than many I've seen before, arguing recent degeneration. Unlike TV,
this self-service medium is what we make of it.