LTspice, a great program, but that UI!

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Every time I want to do something with LTspice I have to fight the UI  
something wicked.  Doing anything relating to commands is pure torture.

I eventually figured out how to do what I wanted, but it is amazing how  
poor not only the UI is, but the documentation.  I have learned  
programming languages by reading the manuals.  But I can't decipher the  
.MEAS statement in LTspice along with many other features.

--  

Rick C

Re: LTspice, a great program, but that UI!
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 Please be advised, LTspice and those like it are real programs designed
for serious users in mind looking for real productivity tools for those  
that are PRODUCTIVE.

 Stop reading the PDF for those game apps.

Jamie


Re: LTspice, a great program, but that UI!
"M Philbrook"  wrote in message  

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Pardon?

http://www.anasoft.co.uk/worstcase.htm

LTSpice is a freebee that lacks major key features for productive,  
professional use, imo...

Anyone can piss about and make a one off work.

-- Kevin Aylward
http://www.anasoft.co.uk - SuperSpice
http://www.kevinaylward.co.uk/ee/index.html


Re: LTspice, a great program, but that UI!
On Sun, 12 Mar 2017 16:46:53 -0000, "Kevin Aylward"

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I get a lot of use out of LT Spice. It just took a few minutes to
figure out the basics of entering a schematic and running a transient
analysis. It's much friendlier than some others that I've used (like
EWB) and a lot cheaper too.

It's easy enough to use that I also use it instead of a calculator,
for simple things like voltage dividers and time constants and opamp
resistor calcs. I confess that I've also used it to design LC filters
by pure fiddling. Instinct and simulation can get you a long way.

The HELP could be a lot better. The spotty HELP make it a lot harder
to do some things. There are other resources online, but they take
some digging, and many just repeat one another. One of the best kept
secrets is the space bar.

I suspect that part of the motivation and value of the Analog Devices
purchase of LTC was LT Spice; a couple of billion dollars worth maybe.
I've heard that ADI will be migrating to LT Spice for their parts.

I wish the scissors icon and the run icon looked more different; I
tend to click the wrong one.


--  

John Larkin         Highland Technology, Inc

lunatic fringe electronics  


Re: LTspice, a great program, but that UI!
"John Larkin"  wrote in message  

On Sun, 12 Mar 2017 16:46:53 -0000, "Kevin Aylward"

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I have to say, no way josa, and ROTFLMAO. :-)

John. Not a chance in a billion that LTSpice has a business worth even  
remotely near that value. Its a freebe, so it would be simply impossible to  
justify it as shareholder value as anything more than dubious "goodwill".

*The* fundamental reason companies buy other companies, is to take their  
*existing customers*, via the *products* that they *sell*. Its because the  
other company is eating into their markets or markets they want to enter.  
Its that simple. It has to be hard profit and loss quantifiable motives,  
that convince investors and shareholders.

I propose that  LTSpice played no part whatsoever in Analog Devices  
decision. Lets see if Mike pops up to contradict me.


-- Kevin Aylward
http://www.anasoft.co.uk - SuperSpice
http://www.kevinaylward.co.uk/ee/index.html


Re: LTspice, a great program, but that UI!
On Sun, 12 Mar 2017 19:42:31 -0000, "Kevin Aylward"

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Observing that Analog Devices simulator is web-based only, "in the
Cloud", I can guess where LTspice is headed >:-}
        
                                        ...Jim Thompson
--  
| James E.Thompson                                 |    mens     |
| Analog Innovations                               |     et      |
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Re: LTspice, a great program, but that UI!
On Sun, 12 Mar 2017 19:42:31 -0000, "Kevin Aylward"

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LT Spice has sold a lot of LT parts.


--  

John Larkin         Highland Technology, Inc

lunatic fringe electronics  


Re: LTspice, a great program, but that UI!
"John Larkin"  wrote in message  

On Sun, 12 Mar 2017 19:42:31 -0000, "Kevin Aylward"

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Maybe, maybe not. How do know? What physical evidence is there of that?



-- Kevin Aylward
http://www.anasoft.co.uk - SuperSpice
http://www.kevinaylward.co.uk/ee/index.html


Re: LTspice, a great program, but that UI!
On Mon, 13 Mar 2017 08:42:25 -0000, "Kevin Aylward"

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The fact that it is available for download, free. And the fact that
other semi makers are offering similar free simulators for their
parts.

And because the LTC people physically told me so last week.


--  

John Larkin         Highland Technology, Inc

lunatic fringe electronics  


Re: LTspice, a great program, but that UI!
"John Larkin"  wrote in message  


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None of that is *evidence* that providing simulators sells any parts at all,  
let alone, lots of parts. Its quite likely that it will improve sales a tad,  
but just how much is guesswork.

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That is some evidence, in the legal sense, but without numbers, and reasons  
for the numbers, it don't mean what they said was accurate or even the  
truth. As I noted, what would you expect them to say. "LTSpice is a total  
loss to us".

When I was designing board level stuff, I would evaluate pretty every single  
semiconductor company for the equivalent part I was planning to design in.  
Its part of the process of being an engineer. You are going to try and get  
the best compromise of performance, cost and availability. It would be just  
insane to design in a part just because that was in the kit of your freebe  
sim tool. Like, you aren't going to check out any alternatives? This is the  
real world. I don't believe any competent engineer would do such a daft  
thing.

So, no, I don't believe that LTSpice makes much of a difference in sales.



-- Kevin Aylward
http://www.anasoft.co.uk - SuperSpice
http://www.kevinaylward.co.uk/ee/index.html


Re: LTspice, a great program, but that UI!
On 3/13/2017 12:26 PM, Kevin Aylward wrote:
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Maybe, maybe not. How do you know? What physical evidence is there of  
that? Your opinion is no better than John's.


Re: LTspice, a great program, but that UI!
On Mon, 13 Mar 2017 17:26:38 -0000, "Kevin Aylward"

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Engineering is expensive. Risk can be expensive. Performance can be
valuable. Getting a product to market matters. There's more to
engineering than minimizing the BOM cost.

https://dl.dropboxusercontent.com/u/53724080/PCBs/TEM2_Power_Board.JPG


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There wouldn't be a tad of jealousy there, huh?


--  

John Larkin         Highland Technology, Inc
picosecond timing   precision measurement  

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Re: LTspice, a great program, but that UI!
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Sure, but one needs to step back a bit here, and examine reality.

Are you really claiming that  a competent  engineer is not even going to  
spend 30 mins on the web. Like *30 min* out of months of development costs,  
simply to check out if another suitable part might even exist?


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No. I have given a lot of thought to what is the value of freebee stuff like  
this, and it is not a lot, imo. The reality is, and taking into account your  
valid comment in principle of minimising development time,  its simple not a  
rational way to develop products to not do even the most minimal check of  
alternative parts. Its even usually a requirement to design, whenever  
possible, a product where you can second source parts.

So, no I don't believe that a competent engineer, using LTSice, will refuse  
to even go on the web for *5 minutes* to check if something else is  
available. Its utter nonsense to suggest that this wouldn't happen. So,  
LTSpice cannot possibly be a genuine *cause* to buy an LT part. The LT part  
will be compared to another part, and the then optimum chosen, and it wont  
matter whether LTSpice is there or not.

This is how advertising works.

The fundamental point of advertisement is to let the customer know that you  
actually exist. Period.

In 1985, if MicroSim did not advertise in magazines, no one would know about  
it.
if Intusoft did not advertise in magazines, no one would know about it.

Once engineers know about them, they *WILL* technically evaluate *which* one  
suits them best. They don't go, oh, ok, I'll just take the first one I find.  
This is not selling perfume.

Today, we have Google. We can all discover TI, Analog Devices  and LT, so  
the value of freebees, today, has been greatly diminished.

An engineering product is designed based on technical, objective  
considerations. Not even spending 5 bloody minutes looking for an  
alternative via Google is fantasy. I don't believe for a second that any  
engineer does this. Once alternatives are discovered, an engineer will  
evaluate them to see if they are a better option.


-- Kevin Aylward
http://www.anasoft.co.uk - SuperSpice
http://www.kevinaylward.co.uk/ee/index.html


Re: LTspice, a great program, but that UI!
On Mon, 13 Mar 2017 20:44:27 -0000, "Kevin Aylward"

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I don't recall saying that.

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Resistors and caps and some ICs are multi-sourced, but not much of the
good stuff is any more.  

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But if I get a good sim of an LTC part and it's not expensive, I just
use it. Their stuff works and doesn't get randomly EOLd like Maxim.

Here's a 2-channel 1200 volt pulse generator.

https://dl.dropboxusercontent.com/u/53724080/PCBs/T840_E1.jpg

(Nice layout, no? I did that one myself.)

I needed a 1400 volt supply, so I pulled up the LTC3803 sim, ran it,
and it looked great so I specified the part and moved on to the hard
parts. It worked just as predicted. (U17, tiny 6-pin bugger, cost
$1.32.)

Was I a Bad Engineer?



--  

John Larkin         Highland Technology, Inc

lunatic fringe electronics  


Re: LTspice, a great program, but that UI!
On Mon, 13 Mar 2017 20:44:27 +0000, Kevin Aylward wrote:

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There's more to it than simply finding the cheapest alternative.
A big part of electronic design is minimizing risk, and to do
that I often use LTspice to simulate parts of the circuit.
Sure I look at the alternatives before choosing a part, but
being able to or not able to simulate a circuit is a big factor.
Another factor that sometimes matters a lot is time.

Once LTspice and another free LT tool called FilterCad was very
helpful for our company - we make modules for ANR headsets,
everything was going great until suddenly we started getting a
lot of returns - bad speakers that would pass factory tests but
rattled when our customer assembled them. They were not amused.
Needed to make a speaker tester and fast! To test a speaker
for distortion I needed to output test tones at various
frequencies then filter the output from a sense mic with a
brick-wall high-pass filter set to twice the test frequency.
With FilterCad I typed in my requirements and it spit out a
complicated circuit using a LTC1068. No way I could have
derived all those values on my own with math in the allotted
time let alone test it - I needed a working solution NOW.
LTspice also had this part, so simulated it and found that
I needed to actively drive the bias pin or it leaked lows,
but otherwise the circuit did what I needed to do, just
needed to supply it with a clock that was 100x more than the
pass frequency.. used an ancient 74HC4059 programmable divider
and a FF to turn my fixed clock into a variable clock.

Unfortunately for LT I just needed one chip and a spare
for the factory tester, but it saved us $thousands and
possibly our jobs. If I ever need something like that again
there it is. For the most part I use LTspice to simulate
generic stuff that doesn't need LT parts (unless I want to,
I use bunches of LTC1050 low-offset opamps), but if faced
with something intense like that filter I'll take a design
with a LT part that I can simulate over something untested
any day, even if it costs a bit more. I'm sure LT sells lots
of parts through their free tools - sure it's advertising
but it's also damn useful.

Terry

Re: LTspice, a great program, but that UI!

On Mon, 13 Mar 2017 20:44:27 +0000, Kevin Aylward wrote:

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That's why I wrote "better option"

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Sure, no one has denied that, but are you, personably, so incompetent that  
you are not able to load in the competitions models form their websites in  
reasonable time?

I doubt it.

So, sure, its useful to have the model includes, but its is trivial detail,  
only of value to those engineers that probably would be better employed  
basket weaving.

I am not talking about the minor, one off, shit, lets just see if this works  
bit. I am referring to standard, professional long term product design,  
where one *IS* subjected to a whole host of constraints like, second  
sourcing, availability, cost, performance etc...

I just don't accept you achieve that by simply using parts, bribed to you,  
by their inclusion in a freebee spice program.


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And illustrates part of the argument I am making.



-- Kevin Aylward
http://www.anasoft.co.uk - SuperSpice
http://www.kevinaylward.co.uk/ee/index.html


Re: LTspice, a great program, but that UI!
On Tue, 14 Mar 2017 20:42:36 +0000, Kevin Aylward wrote:

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uhh... what other switched capacitor active filter chip even
has a spice model? LTspice is also a behavioral simulator (why
it's so fast for switchers) and LT took the time to write behavior
simulations for almost all their analog chips. Other companies,
except for standard parts like opamps, not so much. Not that
I need specific models for simple stuff like that.

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It is not trivial when under the gun. And I suck at making baskets.
  
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My case was a one-off, true, but it was an extremely important
one-off and the solution ended up working so well that if I did
need something like that again I would not hesitate to reuse it.

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Don't have to accept that because I don't, 99% of the stuff
I use LTspice for does not involve using LT parts. I used that
as an example of how it can matter - just because it was a one-off
for me *that time* doesn't mean a similar problem is always a
one-off, could have just as easily been for mass production.

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The claim was that LT sells lots of chips by giving away free
tools, you refuted that claim, I told a story about how once
LTspice saved my bacon. I needed a filter with 0db at center
more than 60db cut at half that frequency, LT gave me the
tools to do that with very little effort (more time to design
the rest of the stuff and write the code) and the end result
worked perfectly. I did look at alternatives, LT's solution
was the best by far. Sure it's not a cheap chip, but for what
it did, the price wasn't bad.. ~$12 single for a precision
70db/octave filter with practically no ripple. How many I
needed personally is not relevant, DK stocks thousands of
them so someone is using the part. I have no doubt that
LT sells oodles of parts because the tools they give away
make the process of using the parts easy and relatively
risk-free.

That said, I still wish it had a better GUI :-)
When I get a chance I'm evaluating SS, it does seem to
have better measurement options.. it's not either/or...

Terry



Re: LTspice, a great program, but that UI!

On Tue, 14 Mar 2017 20:42:36 +0000, Kevin Aylward wrote:

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Don't know, I gave up board level design over 15 years ago :-)

However, if you have the filter as a Laplace transfer function, its pretty  
trivial to input that into any XSpice based simulator, including SS. XSpice  
directly supports Laplace rational numerators/dominators. I do include a set  
of chebys and so forth in SS.

I guess this question sort of really illustrates how many "engineers" that  
are designing electronic products, don't actually know much electronic  
engineering, i.e. how to get a filter cook book and make a model.

I'm an engineer, and for  maybe 12 years, prior to me learning anything  
about Spice internals, I was writing my own models for PSpice.

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This is a misnomer/misconception if this implies others are not. It was a  
marketing ploy to express uniqueness when it wasn't. Even original 1985  
PSpice had behavioural modelling. Spice3/XSPice is behavioural. Its the B  
Source. I have created extensive behavioural models for SuperSpice. I use  
behavioural all the time.

Furthermore, the XSpice bit has full, event driven digital simulation, which  
speeds up analog logic tremendously, way way faster than LTSpice could  
possible dream off. LTSpice don't have mixed-mode at all.

I have some PLL behavioural examples in SuperSpice, one that uses my  
behavioural analog logic libary e.g. fast simulating analog D-Type counters,  
and a version that uses  the XSpice mixed mode engine digital counters.


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Nope. LTSpice buys you 3 times in speed only due to the design of its engine  
core, its behavioural bit has no speed advantage to XSpice at all.

I have SMPS behavioural examples in SuperSpice .

They rus to  full steady state on my Novatech i7 in 7 seconds. Yes, seven  
seconds. So, totally viable to design with.

The bumph that went around late 90s when LTSpice came out, is pretty much  
redundant now. Computers are, maybe 1,000 times faster.

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Anyone that that requires behavioural models for their Spice, I and Jim  
Thomson will be happy to provide such a consulting service, at very  
affordable rates :-)


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My claim, is that it don't sell any where near as some/many claim/think, in  
particular, one poster, who the interested can look up in the thread,  
suggested, $Billions. LT do about $2B a year, so that claim was one of  
ROTFLMAO.


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One off storys don't mean much. Overall principles do. LTSpice is used by  
people to design in parts from ALL manufactures, so it aides people buying  
the competition. *Most* engineers, for *most* projects, DO check out  
alternatives, IMO...


I have a work colleague siting next to me at work, that has used LTSpice for  
years, and still does, despite my urging him to use a real simulator. There  
is just no accounting for taste.  Anyway, he builds pretty big designs in  
them. As far I am aware that has never led to the purchase of an LT Part.

And for reference, to put this "behavioural" misconception to bed.

Spice3 Behavioural D type:

.SUBCKT D_XN !in out outn clk
* _SS_Symbol [C:\ProgramData\AnaSoft\SuperSpice\System\Behavioural.ssm] [D]
*
b1 mid1 0 i=-1e-3*(1-V(clk))*v(!in) -1e-3*V(clk)*v(mid2)
b3 mid2 0 v=0.5*(tanh(20*(v(mid1)-0.5)) + 1)
r1 mid1 0 1k
c1 mid1 0 10f
*
b4 mid3 0 i=-1e-3*V(clk)*v(mid2) -1e-3*(1-V(clk))*v(out)
b6 out 0 v=0.5*(tanh(20*(v(mid3)-0.5)) + 1)
r2 mid3 0 1k
c2 mid3 0 10f
*
b7 outn 0 v=1 - v(out)
*
.ends D_XN

Behavioural XSpice

Laplace Cheby:

.MODEL Chebychev_1DB_3 s_xfer(in_offset=0 gain=1 num_coeff=[0.491307]  
den_coeff=[1 0.988341 1.238409 0.491307] denormalized_freq=1K int_ic=[0.0  
0.0]  )


You know where to find the rest...

-- Kevin Aylward
http://www.anasoft.co.uk - SuperSpice
http://www.kevinaylward.co.uk/ee/index.html


Re: LTspice, a great program, but that UI!
On Wed, 15 Mar 2017 20:32:57 +0000, Kevin Aylward wrote:
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And thus somewhat disconnected with what circuit designer types need.
It's not like designing chips.. it's consuming whatever the chip
makers give me, figuring out the flaws and limitations, balancing
that with cost and other constraints (like time), and when I settle
on something for production hoping the maker doesn't yank it
because it isn't selling enough.

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I no longer care, the design is done, but for future ref.
However this still assumes that the chip maker provides the data,
which by itself still doesn't mean the chip as a system will follow.
If I hadn't have had the LTC1068 model I might not have noticed
that the bypass pin capacitance had a huge effect on low-frequency
pass-through, enough of an effect that I drove it actively to
1/2 supply.
  
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How is using a manufacture-supplied tool to design a circuit with
that manufacturer's part bad designing? Seemed like the thing to do.
Also it in no way means I don't know how to design a filter. Try
designing an ANR filter.. it's a race between amplitude and phase
and all those fancy "known" techniques won't help... it's passive.
Then make it work with crappy 10% ceramic caps (or worse depending
on offset voltage) and speakers and mics with +/-3db variation.
Oh yea the requirements for the filter are unknown, but that's
not even an issue. There's a way to do all that, and it works
perfectly (enough) but it's so obvious that the PhD types
usually don't get it.

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OK
  
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Was gigabucks which I read figuratively as meaning a lot,
didn't take it as a literal number. Thing is if everyone who
used LTspice bought just *one* high-dollar chip, that's likely
millions right there, more than enough to pay a developer.
I see absolutely nothing wrong with a chip maker providing
free tools for their products (I wish more did that), it's
not a bribe, it's interactive documentation and I'm sure it
sells them a lot of parts. Nobody knows precisely how much
because when I buy a chip they don't ask how I found it.
But sales are sales and I have no doubt LTspice adds sales.
  
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??? what principle? that it's useful? You seem to think that
if someone does something one way it means they can't do
something else another way. I do all kinds of stuff from
tubes to microcontrollers to analog micro crap and one thing
I've learned is you don't just learn how to do something
a particular way. If you do that then you're stuck doing it
that way. No, I learned how to quickly learn how to do the
thing I need to do, then move on to the next thing. Next
project is going to be different anyway so it just wastes
time to get all theoretical on something I might never
need again, just document it file it away and if I need
it again there it is.

For a lot of stuff I simply don't care how or why it works,
I just care that it does work. No more than I care about
what kind of current sources a chip uses, it's academic
and doesn't change the outcome. I only care about stuff
like that when something is wrong with the current solution.

Or when there's no solution... for the kinds of filters
I need the most, poles and zeros and Laplace and biquads
get me precisely nowhere.. all that fancy stuff, well,
clips, makes noise, is too sensitive to component variation,
and takes up too much room on the board. And in my head.
If I need it I'll learn it, if not I don't care unless
I'm just curious or something. There is much more to
designing circuits than applying a bunch of fancy math -
it's been my experience that the fancier the math, the
greater the odds it's not going to work in the Real World.
Nature and physics don't give a damn about human equations
and real parts are never the value it says on the packaging.

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They don't care. They're happy if it's used for other things.
If they tried to lock it down then it wouldn't be as useful,
not as popular, less eyeballs seeing LT all the time, fewer sales.
Just as you suspect - it's a billboard. So what.. would be one
thing if it was a scam but their chips work really well.

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Didn't mean to imply that other spice simulators aren't behavioral,
the point was that LT took the time to make netlist and behavioral
models for their parts, even complicated parts. I was under the
impression that there were other optimizations for the smps models.
  
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Real world SK lowpass something...

                                  + sup
                                  |
                                |/c
  in >---150K---*---150K---*----| 2N5089 etc
 (biased        |          |    |\e
 1/2 sup)      470p       220p    |
                |         _|_     |
                `-----------------*---> out
                                  |     (biased
F ~15%0K/45 ~= 3.3khz            22K    1/2 sup
                                 _|_    minus a bit)

...the knobs are easier to turn. Anything much more
complicated than that I'd rather use an app if I need a
standard filter.

Terry

Re: LTspice, a great program, but that UI!
On Thu, 16 Mar 2017 05:50:49 +0000 (UTC), Terry Newton

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If you need to design serious LC filters, the NuHertz software may be
worth it. In a few minutes, it designed a filter that we'd spent days
struggling with. It can use standard values and finite Qs and designs
filter forms that most people have never heard of.



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I recently designed a one-side-absorptive LC lowpass by pure fiddling
in LT Spice. It has 5 parts, which is about the limit of a
fiddlable-design, or past the limit for some topologies. In my filter,
various causalities seem to be sort of orthogonal, so fiddling
converged. In the other one, the NuHertz solution, things diverged;
fidddling just kept making things worse.

Somebody should do research on the dynamics of fiddling. Maybe it's
been done.


--  

John Larkin         Highland Technology, Inc

lunatic fringe electronics  


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