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Circuit simulation software

Kevin said:
Oh dear...

You've not designed an analogue ic with 10,000 transistors have you?

Your right I haven't, which 1 did you do? Has anyone ever done it with
"super spice" ?

This thread has nothing to do with chip design.


How do you propose to do worst case corners or Monty Carlo to verify
that your rats nest custom tweaked, one off circuit actually works with
component variations?

No reason why to cant simulate a curcuit after you have it working if
you needed that information but the components with the biggest
variation are semiconductors and iv'e not seem a Monty Carlo test that
included their variables but it's been a while so maybe.
You simply can not design analogue i.c.s without extensive simulation.
Ideally, bench work is kept to a bare minimum. Typically, analogue ics
are so well designed using only simulation that bench work often
consists of simply verifying a few bits and bobs and making the data
sheet. This is way it is.

Again this thread has nothing to do with chip design.
 
I

Ian Bell

Jan 1, 1970
0
Kevin said:
Rich Grise wrote:

well, I don't know who this originated from or by how so..

I didn't say that although it appears to be atributed to me.
Oh dear...

You've not designed an analogue ic with 10,000 transistors have you?

I did say that.

Don't know who said that and not sure what it was in reply to - surely not
my comment?

Please trim you attributions accurately guys.

Ian
 
J

Jim Thompson

Jan 1, 1970
0
On 17 Jun 2006 04:13:57 -0700, [email protected] wrote:

[snip]

You are a rank amateur with NO real experience using simulators.

And you probably consider yourself to be an engineer, but you're NOT
;-)

...Jim Thompson
 
J

John Larkin

Jan 1, 1970
0
Getting anything usefull from a simulator is usually much harder than
building the circuit and mearuring its performance.


Neither breadboarding nor simulation is a safe substitute for design.
I rarely simulate, and rarely breadboard, and then just a few parts
tacked together. We think, design, lay out multilayer boards, let
Production build a couple, and test them. Most are sellable first try.

We don't measure a product's performance so much as we predict it and
sell it, then verify.

John
 
Jim said:
On 17 Jun 2006 04:13:57 -0700, [email protected] wrote:

[snip]

You are a rank amateur with NO real experience using simulators.

Ive had them for 20+years, I dont use them much because they dont help
me any for the work I do, they may help you I wouldnt know.
And you probably consider yourself to be an engineer, but you're NOT

How would you know?

Sounds like the rantings of someone who's lost the arguement. Dont
stamp your foot down too hard at your age.
 
J

Jim Thompson

Jan 1, 1970
0
Jim said:
On 17 Jun 2006 04:13:57 -0700, [email protected] wrote:

[snip]

You are a rank amateur with NO real experience using simulators.

Ive had them for 20+years, I dont use them much because they dont help
me any for the work I do, they may help you I wouldnt know.
And you probably consider yourself to be an engineer, but you're NOT

...Jim Thompson

How would you know?

"Getting anything usefull from a simulator is usually much harder
than building the circuit and mearuring its performance" ranks right
up there with most stupid statement of the year (even after ignoring
the illiterate spellings).
Sounds like the rantings of someone who's lost the arguement. Dont
stamp your foot down too hard at your age.

I didn't know there WAS an argument.

...Jim Thompson
 
K

Kevin Aylward

Jan 1, 1970
0
John said:
Neither breadboarding nor simulation is a safe substitute for design.

The facts are truly that 10,000s of analogue ics engineers simulate as
the main bread and butter tool of design, for 40 hours a week and
produce billions of chips. Its just the way it truly is. No amount of
banter is going to change the facts that is done every f*&^%ing day of
the week at companies such as linear technology, analogue devices, Texas
Instruments, Intersil, On-semi conductor. The list is endless.
Unfortunately, many just don't have the knowledge as to what is actually
done at these companies, no matter how many times I try to point out the
real, verifiable facts.
I rarely simulate, and rarely breadboard, and then just a few parts
tacked together. We think, design, lay out multilayer boards, let
Production build a couple, and test them. Most are sellable first try.

You are probably not designing complex transistor level circuits.
Anything more than 2 transistors is not truly solvable by hand. I would
like anyone do an accurate pole-zero calculation of even a 4 transistor
circuit, and this don't even account for non-linear storage, or
non-linear capacitor effects.

The reality is that despite having a good handle on the overal operation
of complex circuits, without simulation, one knows nothing about how the
circuit will really work in detail.

People need to get out of this, pen ana paper is the only way "real"
engineers design. Like, consider solving the equations for colliding
black holes. Like, you think people can do this by hand?

Most modern products now are too complex to do without extensive
simulation.
We don't measure a product's performance so much as we predict it and
sell it, then verify.

Ahmm...


Kevin Aylward B.Sc.
[email protected]
http://www.anasoft.co.uk
SuperSpice, a very affordable Mixed-Mode
Windows Simulator with Schematic Capture,
Waveform Display, FFT's and Filter Design.

"There are none more ignorant and useless,than they that seek answers
on their knees, with their eyes closed"
 
K

Kevin Aylward

Jan 1, 1970
0
Your right I haven't, which 1 did you do?

I am working on one right now. Quite impossible without simulation.
Has anyone ever done it with
"super spice" ?

To be fair, SS is not really designed for circuits that large. It will
simulate them, but its not really up to speed for that size of a job.
However, it has been used extensively for ic building blocks.

For the above larger job I am using Cadence/Spectre.
This thread has nothing to do with chip design.

Its to do with analogue design. IC design is being illustrated to show
just how daft the idea that:

"getting anything usefull from a simulator is usually much harder han
building the circuit and mearuring its performance."

is.

With all due respect to the writer, the writer of that statement has
very limited knowledge of professional analogue design.

No reason why to cant simulate a curcuit after you have it working if
you needed that information but the components with the biggest
variation are semiconductors and iv'e not seem a Monty Carlo test that
included their variables but it's been a while so maybe.

Again, with all due respect, all this shows is that you are quite
ignorant of 10,000s professional analogue designers and the tools such
designers use on a daily basis. Monty carlo and worst case simulations
are de-facto standard to produce a reliable product in short time
scales. Many tools have specific support for these features.

This debate is pretty much futile as its unlikely you will be able to
take your blinkers off and accept what is actually known and done by
10,000s of professional analogue designers. Its 40 hours a week running
sims. That's just the way it is, mate.
Again this thread has nothing to do with chip design.

Its about analogue design, and as such, for anything other than a micky
mouse 2 transister circuit, simulation tools are, in todays market
place, indespensible.


Kevin Aylward B.Sc.
[email protected]
http://www.anasoft.co.uk
SuperSpice, a very affordable Mixed-Mode
Windows Simulator with Schematic Capture,
Waveform Display, FFT's and Filter Design.

"There are none more ignorant and useless,than they that seek answers
on their knees, with their eyes closed"
 
Kevin said:
I am working on one right now. Quite impossible without simulation.

Quite so.
Its to do with analogue design. IC design is being illustrated to show
just how daft the idea that:

My answer addresses the question that was ASKED not the one you wanted
asking.
"getting anything usefull from a simulator is usually much harder han
building the circuit and mearuring its performance."

is.

With all due respect to the writer, the writer of that statement has
very limited knowledge of professional analogue design.

Again the OP wanted something CHEAP, not something professional.

Again, with all due respect, all this shows is that you are quite
ignorant of 10,000s professional analogue designers and the tools such
designers use on a daily basis. Monty carlo and worst case simulations
are de-facto standard to produce a reliable product in short time
scales. Many tools have specific support for these features.

You didnt actually answer the point.

This debate is pretty much futile as its unlikely you will be able to
take your blinkers off and accept what is actually known and done by
10,000s of professional analogue designers. Its 40 hours a week running
sims. That's just the way it is, mate.

Thats my point it takes an awfull lot of effort to get anything usefull
from a simulator.

Its about analogue design, and as such, for anything other than a micky
mouse 2 transister circuit, simulation tools are, in todays market
place, indespensible.

Again you didn't read the question that was asked. Cheap AND usefull?
Ihaven't seen it yet.
 
M

mc

Jan 1, 1970
0
Kevin Aylward B.Sc.
From this tag line do we infer bias against Christianity and perhaps other
religions on the part of Anasoft?

Besides, who is being quoted?
 
J

John Larkin

Jan 1, 1970
0
This debate is pretty much futile as its unlikely you will be able to
take your blinkers off and accept what is actually known and done by
10,000s of professional analogue designers. Its 40 hours a week running
sims. That's just the way it is, mate.

Cool. I can design something that I *know* will work in a few hours,
and then I can goof off the other 37 hours of the work week.

John
 
J

Jim Thompson

Jan 1, 1970
0
Cool. I can design something that I *know* will work in a few hours,
and then I can goof off the other 37 hours of the work week.

John

Cool. Show me your 40 pages of schematic that you designed without
any preliminary breadboarding or simulation.

...Jim Thompson
 
J

Jim Thompson

Jan 1, 1970
0
From this tag line do we infer bias against Christianity and perhaps other
religions on the part of Anasoft?

Strikes me as a general comment on ALL who follow such a religious
dictum.
Besides, who is being quoted?

Inquiring minds want to know ;-)

...Jim Thompson
 
J

Jim Thompson

Jan 1, 1970
0
Quite so.


My answer addresses the question that was ASKED not the one you wanted
asking.


Again the OP wanted something CHEAP, not something professional.



You didnt actually answer the point.



Thats my point it takes an awfull lot of effort to get anything usefull
from a simulator.



Again you didn't read the question that was asked. Cheap AND usefull?
Ihaven't seen it yet.

Sounds like we have a reincarnation of Royal Fuchs or crazy frog.
PLONK!

...Jim Thompson
 
M

Michael A. Terrell

Jan 1, 1970
0
Jim said:
Sounds like we have a reincarnation of Royal Fuchs or crazy frog.
PLONK!


I've had him kill filed for years. That line sounds like it should
have been on top of the first page of instructions for his "spice"
package.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida
 
J

Jim Thompson

Jan 1, 1970
0
I've had him kill filed for years. That line sounds like it should
have been on top of the first page of instructions for his "spice"
package.


No. No. I meant [email protected] was the reincarnation.

I agree with Kevin ;-)

...Jim Thompson
 
J

John Larkin

Jan 1, 1970
0
Cool. Show me your 40 pages of schematic that you designed without
any preliminary breadboarding or simulation.

...Jim Thompson


I could show you a thousand. The last project I did, a temperature
controller/pulsed gradient driver, had no sim or breadboarding. This
week's gadget, a sub-ns singlemode laser driver, will have none
either.

About the only time I ever breadboard is when a part is poorly
characterized, and then I only test a single part or a very simple
circuit involving the part, like when I TDRd a trimpot last week to
see just how high a frequency signal can be trimmed with a pot. Ditto
simulation, just little snippets, usually for nonlinear control loop
tweaking, based on idealized component models. I never breadboard or
simulate an entire product. I design maybe 10 products a year and fire
up a simulator two or three times a year at most.

I do appreciate that it makes sense to simulate an IC design, but I
don't do IC design. I do FPGA design, but don't simulate that either.

Really, designing is a good investment in time. That especially
applies to software, where most programmers spend four times as long
debugging ("breadboarding") as they do coding, and have the same
problem as hardware breadboarders have, namely that ad-hoc debugging
never finds all the bugs. My ratio is more like 4:1 in the other
direction, not because I'm so smart, but because I *know* I'm not
smart enough to speed-type reliable code without looking back.

I think that the worst part of design by simulation/breadboarding is
the bad-habits-training loop that results.

John
 
J

Jim Thompson

Jan 1, 1970
0
I could show you a thousand. The last project I did, a temperature
controller/pulsed gradient driver, had no sim or breadboarding. This
week's gadget, a sub-ns singlemode laser driver, will have none
either.

About the only time I ever breadboard is when a part is poorly
characterized, and then I only test a single part or a very simple
circuit involving the part, like when I TDRd a trimpot last week to
see just how high a frequency signal can be trimmed with a pot. Ditto
simulation, just little snippets, usually for nonlinear control loop
tweaking, based on idealized component models. I never breadboard or
simulate an entire product. I design maybe 10 products a year and fire
up a simulator two or three times a year at most.

I do appreciate that it makes sense to simulate an IC design, but I
don't do IC design. I do FPGA design, but don't simulate that either.

Really, designing is a good investment in time. That especially
applies to software, where most programmers spend four times as long
debugging ("breadboarding") as they do coding, and have the same
problem as hardware breadboarders have, namely that ad-hoc debugging
never finds all the bugs. My ratio is more like 4:1 in the other
direction, not because I'm so smart, but because I *know* I'm not
smart enough to speed-type reliable code without looking back.

I think that the worst part of design by simulation/breadboarding is
the bad-habits-training loop that results.

John

I design on paper, then test by simulation.

I do note that you admit to regular failures. My rate of need for
debug is under 1%... usually due to the customer's failure to spec
what he really wanted.

...Jim Thompson
 
D

Don Bowey

Jan 1, 1970
0
From this tag line do we infer bias against Christianity and perhaps other
religions on the part of Anasoft?

Who cares?
Besides, who is being quoted?
You haven't been around here very long, so I will clue you in......

In Kevin's view, only Kevin is worth quoting. I think it is 95% because he
is usually correct and 5% because he argues to win even when he is wrong,
and knows it. It's kind of like trying to discuss things with his Texan
alter ego.

Don
 
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