LTspice, a great program, but that UI! - Page 6

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Re: LTspice, a great program, but that UI!
John Larkin wrote...
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 I'm a longtime user of Intusoft's SPICE.  It has
 superior schematic entry and output graphing and
 both are more amenable to publishable stuff.  I've
 played with LTSpice on and off, but the UI sucks
 and I'm not impressed with the graphing, except
 maybe for super-long plots for SMPS evaluation,
 what it was designed for in the first place.


--  
 Thanks,
    - Win

Re: LTspice, a great program, but that UI!
On 12 Mar 2017 14:30:54 -0700, Winfield Hill

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Most of LTspice's won't run on any other simulator... which I consider
to be a very STUPID marketing move.

And it was done quite purposefully... several years ago I noticed that
updates were replacing Berkeley-compliant models with encrypted
versions that run only on LTspice, so I quickly saved all their models
to a separate directory.

So I only use LTspice to verify that my model writings will run there
as well as on Berkeley-compliant simulators... at the insistence of
clients ;-)

As for the UI sucking... sucking a Chandler Heights (*) sized LEMON...
usually the size of soft balls... for those of you unaware of the
Arizona citrus trade.

(*) Two miles to the west of me.

As for IntuSoft's Spice, pretty good simulator engine, but GUI and
post-processing still not up to original-flavor MicroSim PSpice (which
I have used since DOS days with hand-written netlists :-)
        
                                        ...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 14:48:34 -0700, Jim Thompson wrote:

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PSpice is probably the best implementation ever ever ever.

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

Always reminds me of:

Bodacious cowboys
Such as your friend
Will never be welcome here
High in the Custerdome

Steely Dan - Gaucho

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PSpice was very good. Where do you think I stole the idea for moving around  
testpoints on the schematic?

I used PSpice from around 1985 to 1997, whilst I was a board level designer,  
paid for at the various companies I worked at. I commenced the SS project as  

night time work and 150,000 lines of code...

I checked out IntuSoft during that period, and rejected it  immediately I  
discovered that you had to put 0V voltage sources in leads to plot currents.  
A total no, no. Pspice has .probe, you get everything.

I checked out ALL the spices at the time, none were usable. That's *why* I  
wrote SS. I needed a usable Spice, personally.

When I got the Berkeley Spice3/XSpice code, around 1997, I discovered that  
the BSim3 model code did not actually provide terminal currents for the  
gate, drain and bulk. So, my first task was to spend a week or so, trial and  
erroring adding up the various terms in the data structures to get the total  
current from all the individual bits. The issue being, is that its a no  
documentation, student written bunch of spaghetti.


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


Re: LTspice, a great program, but that UI!
Kevin Aylward wrote:
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Speaking of UI, your site says the student version of Superspice has UI  
limitations.  That seems odd because usually apps have functional  
limitations.  What is limited in the UI?




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

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Essentially, not a lot. "GUI functions" means the checkbox for parameter  
sweeps don't work. This is, of course, to limit some functionality to entice  
the user to upgrade. The astute user will notice that they can make a  
"rerun" file with the appropriate commands (described in the help) to run  
multicomponent parameter sweeps, with the appropriate extra "include" file  
telling SS to use that rerun file.

Other than what ever produces the functional limitations described, the GUI  
behaves the same.

However..., if someone sends the appropriate "I am very poor" begging email,  
I am liable to send the Pro with only the non commercial use restriction.  
All money I get for SuperSpice goes to my 80 year old mother.

If anyone wants the XSpice VC++ code, they can have that as well.

-- 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 17/03/17 19:23, Kevin Aylward wrote:
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Do you mean the XSpice referred to here?
<http://ngspice.sourceforge.net/xspice.html>
If not, then what does your XSpice do?

Clifford Heath.

Re: LTspice, a great program, but that UI!
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On 17/03/17 19:23, Kevin Aylward wrote:
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Yes and No. SS does not use ngspice. ngspice is a derivative of the Georgia  
Tech XSpice, which is a derivative of Spice3. Georgia Tech added the digital  
mixed mode engine and "A code models".

SS uses my port and modified XSpice code.

<http://ngspice.sourceforge.net/xspice.html>
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My XSpice port has all the stuff I added to make it have the features that  
SS needs. For example, worst case and monte carlo support.

Details like allowing for direct access/plotting to BSim3 transient and dc  
terminal currents. The base code requires a manual insertion of 0V sources.


I recently added

http://www.anasoft.co.uk/MOS1Model.htm

I got my base code around 1996 or so. I have made around 10,000 lines of  
changes and additions.


-- 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 18/03/17 21:41, Kevin Aylward wrote:
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It sounds like the ngspice guys would be happy if someone found the  
energy to merge your improvements. I wish I had time for another  
project, but that's always been the case :)


Re: LTspice, a great program, but that UI!
"Clifford Heath"  wrote in message  

On 18/03/17 21:41, Kevin Aylward wrote:
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I did give one of their Administrators by code for my magnetic non-linear  
hysteresis model. Its the same basic implementation that is in LTSPice,  
although don't converge as good.

I don't have any problems in ngspice implementing my MOS1 mods. I did that  
in part to put one over on Mike. It makes the MOS1 compatible with LTSpice's  
VDMOS model, but with some enhancements. It helps all by having a common  
implementation of a discrete mosfet.


-- 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 12 Mar 2017 14:30:54 -0700, Winfield Hill

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I don't publish stuff, I sell stuff; different application. I see
nothing wrong with the schematic entry or the graphing. I can enter
and sim a simple circuit in a couple of minutes. I have sent screen
shots to customers and put them in manuals. They are plenty good
enough.

 I've
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I works fine for me.  

--  

John Larkin         Highland Technology, Inc

lunatic fringe electronics  


Re: LTspice, a great program, but that UI!
On Sun, 12 Mar 2017 14:16:22 -0700, John Larkin wrote:

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Kev is obviously heavily biased against LT because he views it as a free  
and unwelcome alternative to his SS, so his denigratory remarks have to  
be seen in that light.


Re: LTspice, a great program, but that UI!
On Sun, 12 Mar 2017 22:00:02 -0000 (UTC), Cursitor Doom

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I take it you've used neither?
        
                                        ...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 22:00:02 -0000 (UTC), Cursitor Doom

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Lotsa Spice Snobs here.


--  

John Larkin         Highland Technology, Inc

lunatic fringe electronics  


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

On Sun, 12 Mar 2017 14:16:22 -0700, John Larkin wrote:

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Simply not true. I wrote SS for *ME*.  I wrote it after evaluation all  
available spices at the time around 1996. Other than, PSpice, they all had  
shit GUIs. Any money I get from SS, goes straight to my 80 year old mother,  
not me.

I give an accurate, non biased view, as an engineer. Period. Believe what  
you want.

I have repeatedly stated that LTSpice, to my knowledge, has the fastest and  
best convergence of any PC Spice. However, its GUI, is a joke. Seriously.  
For me, its the twilight zone how anyone can find its GUI ok. If the GUI was  
usable, I would be using it. I want the best speed and convergence and  
features myself. Dah...

LTSpice simply does not have the core features that I *need* and use *every*  
day, as a companion to Cadence Virtuoso in my professional IC design work.

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

Having to press a menu/function key just to move a component, is just  
insane....


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


Re: LTspice, a great program, but that UI!
"Kevin Aylward"  wrote in message  


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I will expand on that, in part this will give a bit of general knowledge as  
to what "pro ic design is all about" that readers here may find useful.

Key parameters in producing a commercial IC product are.

1 It takes several months to get a design back from the fab after tapeout.
2 ICs, typically today, are complicated, 10,000s of transistors for an  
analog ASIC
3 A 0.18u process might take $100k in prototype fab costs
4 Fab process have extensive variations
5 Millions sold per month must work, reliably, for many years.

So, prior to tapeout, an ic designs are required to have extensive design  
effort and verification.

The process of designing, say a BiCMOS chip, involves going through a range  
of design optimisations and simulations. This consists of designing for DC,  
AC TRAN, NOISE, in an iterative manner.

The details of the design involve selecting, for example, gate lengths and  
widths, and how many in parallel and series, and emitter areas. For example,  
shorter gate lengths get you faster speed. Maximising headroom may be  
achieved by reducing the Vdsat of the transistor, by reducing its overdrive  
voltage, Vgst (Vgs-Vth), this means say, increasing the ratio of W/L.  
However, reducing Vgst, makes matching worse, so compromises have to be  
made. Better matching means larger W x L, however, this means a slower  
circuit, which could mean instability in a feedback loop. etc...etc... all  
to satisfy specifications of power consumption, noise, die size,  
etc...etc...

Now, all of this has to be done with process variations, say Vt varying by  
200mv, gm of mosfet varing 20%, and over temperatures, say -40 deg to 85deg,  
over all supply voltages. Typically models are made that reflect the  
extremes of the process, which I explain in more detail here:

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

Typically, 100,000s of simulations are run to verify a chip before tapeout.

So, no, I do not have "bias". My view is based on the facts.

If a simulator does not directly support worst case analyses, its dead in  
the water as far as IC design in concerned. Period.

Second, is usability of accessing key data that supports the above design  
issues. IC design requires spending hours per day, every day, running  
continually modified simulations. Pissing about for a minute to access each  
plot *is* a major problem, for serious, professional designers.

For example, in checking that Vds (drain voltage) is greater than Vdsat  
(when device crushes) over *all* process corners, and over the operating DC  
ranges, one needs to be able to do this *easily*.

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

Scroll down to the second screen shot.

This shows a signal list tab to the left where you can ctrl-click and easily  
display a combination of any signal. For example, plotting  Vgs and Vdsat.  
SuperSpice lists in that signal list all major device parameters such as  
Vgst, gm, gds, etc... You don't have to hunt about to get the data that you  
really need to plot.

Even small details can have a *major* effect on usability when your  
simulating 40 hours per week. For example, SS displays the actual x, y trace  
data of the graph without cursors, because the mouse cursor *locks* onto the  
trace, and only displays only the *valid* y with x data. LTSpice just  
displays apparent x,y data of whether the mouse is on the screen, which has  
nothing to do with the real trace data. Using LT manual cursers is a major  
pain.

So, sure, if your not an IC design pro, the LT GUI, may well be adequate for  
your needs.

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


Re: LTspice, a great program, but that UI!
Great post on a great thread.

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

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We call people who think like you "Blue Wire Queens" >:-}

Chips generally aren't tweakable... they either work, or they don't.
        
                                        ...Jim Thompson
--  
| James E.Thompson                                 |    mens     |
| Analog Innovations                               |     et      |
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Re: LTspice, a great program, but that UI!
snipped-for-privacy@kevinaylward.co.uk says...
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 Did you fart ?
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Re: LTspice, a great program, but that UI!
May be it looks a little bit home made and uses odd shortcuts but it has  
one feature that makes entering schematics as fast as no second program  
I know:
There is no need to place wires from pin to pin! Just place a few parts,  
then draw a wire right through them and when you end the wire (right  
click or escape) all lines that would short a component magically disappear.
Also, if you place a component right over a wire, the piece of wire  
under the component is automatically deleted.
Frequently used components like resistors, inductors, diodes or ground  
symbols can be inserted without moving the mouse to a menu by typing r,  
l, d or g.
Rotate is ctrl-r but mirror is _not_ ctrl-m :-(
Anyhow, very nice imho!

Robert


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