I've changed a voltage source from, say, sine to pulse, and had the dialog box params get scrambled, the same problem as switching between time and frequency simulation. Apparently a smart editor is too dumb to realize that it's editing the wrong kind of line.
Default rise and fall times are wild.
I found an actual bug in LT Spice that crashed it. I emailed Mike, who was in Hungary or somewhere, and he sent me a fixed binary in a couple of hours.
-- John Larkin Highland Technology, Inc The cork popped merrily, and Lord Peter rose to his feet. "Bunter", he said, "I give you a toast. The triumph of Instinct over Reason"
I hope not. It's a specific strategy to make enough profit on low volumes to create specialized parts that are super- helpful to engineers working on unique problems. They make enough $$ to well document their designs. This might all go away if AD makes big changes.
--
Thanks,
- Win
Change is inevitable, progress is not.
-- Rick C. + Get 1,000 miles of free Supercharging + Tesla referral code - https://ts.la/richard11209
Why should they? They sell into exactly same market.
The AD797 (which doesn't have the vices that the LT1028 does) sell for about $20.
That's about twice what Mouser are asking for the LT1028.
Not altogether surprising. The process Analog Devices uses to manufacture the AD797 is remarkably fancy.
-- Bill Sloman, Sydney
Bill Sloman wrote: ...
manufacture the AD797 is remarkably fancy.
Can you shed some light?
-- Uwe Bonnes snipped-for-privacy@elektron.ikp.physik.tu-darmstadt.de
Institut fuer Kernphysik Schlossgartenstrasse 9 64289 Darmstadt
--------- Tel. 06151 1623569 ------- Fax. 06151 1623305 ---------
Not a lot. I can recall talk of ion-implanted PNP transistors that were rea lly fast, high gain parts, and some comment to the effect that it was a 20- stage process, where regular processes were about 12 stages, but it was all from some Analog Devices presentation, and I haven't been to one for a dec ade or so.
Googling did reveal that Analog Devices still make their high-end analog pa rts and MEMS parts in-house, rather than relying on foundries, but nothing all tht specific.
-- Bill Sloman, Sydney
eally fast, high gain parts, and some comment to the effect that it was a 2
0-stage process, where regular processes were about 12 stages, but it was a ll from some Analog Devices presentation, and I haven't been to one for a d ecade or so.parts and MEMS parts in-house, rather than relying on foundries, but nothin g all tht specific.
I would expect that given the equipment doesn't get out of date as fast as the state of the art stuff used for making advanced digital chips. So they can continue pounding out the same parts using fully depreciated assets.
I was very surprised to recently learn that Intel is no longer the point of the spear when it comes to process technology which I likely read here som ewhere. Seems abandoning fabs at the bleeding edge is the better way to go . One has to assume AMD is paying through the nose to use TSMC's bleeding edge processes, but smaller chips are cheaper chips with more profit margin with all else being equal. Once you get into the huge volumes they have a ll else is pretty much equal.
Some years ago I told a friend to ditch AMD stock. With nearly a 1 year le ad in process technology Intel was likely out of AMD's reach forever. Gues s I got that one wrong.
-- Rick C. -- Get 1,000 miles of free Supercharging -- Tesla referral code - https://ts.la/richard11209
Mike's 2018 interview says that his main job at AD is creating AD part models in LTSpice
His linkedIn profile says he's at AD---does someone has a source quote for his leaving?
really fast, high gain parts, and some comment to the effect that it was a 20-stage process, where regular processes were about 12 stages, but it was all from some Analog Devices presentation, and I haven't been to one for a decade or so.
g parts and MEMS parts in-house, rather than relying on foundries, but noth ing all that specific.
s the state of the art stuff used for making advanced digital chips.
They might have less of a drive to get the highest possible resolution, and anyway ion implantation can offer you that rather more cheaply than optica l techniques anyway - and has been able to do that for ages. It's as slow a s a wet week, so you can only have the high resolution at a few critical sp ots on the device, which is probably all you need for something like the AD
797Analog parts do tend to be less modular than digital parts.
You probably need to think about the state of the relevant art, rather than thinking that making big fast digital chips is the only art that matters.
assets.
That's probably not the way they see it.
-- Bill Sloman, Sydney
"Intuition is the most important part of engineering."
That's great.
-- John Larkin Highland Technology, Inc The cork popped merrily, and Lord Peter rose to his feet. "Bunter", he said, "I give you a toast. The triumph of Instinct over Reason"
re really fast, high gain parts, and some comment to the effect that it was a 20-stage process, where regular processes were about 12 stages, but it w as all from some Analog Devices presentation, and I haven't been to one for a decade or so.
log parts and MEMS parts in-house, rather than relying on foundries, but no thing all that specific.
as the state of the art stuff used for making advanced digital chips.
nd anyway ion implantation can offer you that rather more cheaply than opti cal techniques anyway - and has been able to do that for ages. It's as slow as a wet week, so you can only have the high resolution at a few critical spots on the device, which is probably all you need for something like the AD797
You haven't said anything about the technology required to make the parts. That's my point. I think continuing to advance analog design doesn't take the same level of investment as it does for digital designs.
an thinking that making big fast digital chips is the only art that matters .
How about sticking with what I said rather than what you imagine I said. I never said anything about the worth of design art. I was talking solely a bout the cost of production. Most analog designs have fundamental limitati ons in how small they can be due to power handling. It doesn't really matt er so much how many transistors you stuff into the innards of a regulator b ecause the area of the chip will be dominated by the power handling compone nts. So not as much incentive to continue to miniaturize.
ed assets.
You mean they buy new fab lines just so they can start the depreciation cyc le over again? Even then, the costs of starting a typical lnew analog desi gn is so much less than a digital design that they can afford to have many devices with much lower production volumes.
You really haven't addressed the meat of anything I've mentioned.
Analog designs are cheaper to start and cheaper to produce. So it is more practical to have lots of designs that aren't super high volume which is si mply not the case for digital designs that are anywhere at all near state o f the art.
-- Rick C. -+ Get 1,000 miles of free Supercharging -+ Tesla referral code - https://ts.la/richard11209
It's actually insane, but if intuition is all you've got, you might agree.
-- Bill Sloman, Sydney
were really fast, high gain parts, and some comment to the effect that it w as a 20-stage process, where regular processes were about 12 stages, but it was all from some Analog Devices presentation, and I haven't been to one f or a decade or so.
nalog parts and MEMS parts in-house, rather than relying on foundries, but nothing all that specific.
st as the state of the art stuff used for making advanced digital chips.
and anyway ion implantation can offer you that rather more cheaply than op tical techniques - and has been able to do that for ages. It's as slow as a wet week, so you can only have the high resolution at a few critical spots on the device, which is probably all you need for something like the AD797
.I did mention ion-implantation.
e the same level of investment as it does for digital designs.
than thinking that making big fast digital chips is the only art that matte rs.
I never said anything about the worth of design art. I was talking solely about the cost of production. Most analog designs have fundamental limita tions in how small they can be due to power handling.
Some do. Cambridge Intruments sold an electron beam microfabricator to Thom pson in the early 1980s.
The acceptance test was to direct write the very narrow gates on three wafe rs of very high frequency FETs.
Someone looked at the price Thompson CSF was charging for those FETs and th ose three wafers would have paid the million dollar price of the machine.
innards of a regulator because the area of the chip will be dominated by t he power handling components. So not as much incentive to continue to mini aturize.
Regulators aren't what we were talking about. If you need fine-line structu res to get local speed, your argument falls flat.
ated assets.
ycle over again?
Incremental development doesn't necessarily involve buying a new fab line.
less than a digital design that they can afford to have many devices with m uch lower production volumes.
The cost of working out how to get better performance out of a nominally st andard analog design can be appreciable - you may be talking about less num erous elements, but you have to be much pickier about how each elements beh aves.
Not in terms you seem to be willing to think about.
They can be. The step up from the LT1028 to the AD797 (which is actually a simpler circuit) may not have been all that cheap.
lume which is simply not the case for digital designs that are anywhere at all near state of the art.
The state of the art for digital designs is not inter-changable with the st ate of the art for analog designs. You've got different constraints and dif ferent targets. A fab line optimised to produce high performance analog isn 't going to look much like a fab line optimised to produce any of the vario us flavours of high performance digital parts.
And of course Analog Devices has a separate fab line designed to produce ME MS (micro-electro-mechanical) parts.
-- Bill Sloman, Sydney
t were really fast, high gain parts, and some comment to the effect that it was a 20-stage process, where regular processes were about 12 stages, but it was all from some Analog Devices presentation, and I haven't been to one for a decade or so.
analog parts and MEMS parts in-house, rather than relying on foundries, bu t nothing all that specific.
fast as the state of the art stuff used for making advanced digital chips.
n, and anyway ion implantation can offer you that rather more cheaply than optical techniques - and has been able to do that for ages. It's as slow as a wet week, so you can only have the high resolution at a few critical spo ts on the device, which is probably all you need for something like the AD7
97ts.
Yes, you mentioned it again, but neither time was relevant to the issue.
ake the same level of investment as it does for digital designs.
r than thinking that making big fast digital chips is the only art that mat ters.
. I never said anything about the worth of design art. I was talking sole ly about the cost of production. Most analog designs have fundamental limi tations in how small they can be due to power handling.
ompson in the early 1980s.
fers of very high frequency FETs.
those three wafers would have paid the million dollar price of the machine.
he innards of a regulator because the area of the chip will be dominated by the power handling components. So not as much incentive to continue to mi niaturize.
tures to get local speed, your argument falls flat.
Not really. What analog production devices are you suggesting have that so rt of fine line requirement that digital devices do today?
ciated assets.
cycle over again?
.Exactly! In the digital domain they have no choice but to build entirely n ew fab lines every year or two. With the technology required to build anal og devices this is not so much the case and nothing remotely like the expen se of the digital fab lines is needed.
h less than a digital design that they can afford to have many devices with much lower production volumes.
standard analog design can be appreciable - you may be talking about less n umerous elements, but you have to be much pickier about how each elements b ehaves.
Which has very little to do with the issue at hand. The bottom line is des igning and fabrication costs of analog are much, much lower than today's di gital chips.
Not in any meaningful terms. You are just bobbing and weaving without sayi ng anything meaningful.
a simpler circuit) may not have been all that cheap.
Yes, I'm sure it was not "all that cheap". But compared to the digital des igns today it was a pittance which is my point. Maybe the AD797 is a chip that can only be profitable at higher volumes, I don't know. But most of t he analog chips ADI and LT make are not high volume chips but are still pro fitable because of the lower costs than with many digital devices.
volume which is simply not the case for digital designs that are anywhere a t all near state of the art.
state of the art for analog designs. You've got different constraints and d ifferent targets. A fab line optimised to produce high performance analog i sn't going to look much like a fab line optimised to produce any of the var ious flavours of high performance digital parts.
I never said they were equivalent. I said the costs of maintaining state o f the art digital processing requires huge volumes which aren't required fo r most analog designs.
MEMS (micro-electro-mechanical) parts.
More red herrings.
Ok, I think we have covered this completely. Continue on your own if you w ish. You aren't adding anything to the conversation at this point.
-- Rick C. +- Get 1,000 miles of free Supercharging +- Tesla referral code - https://ts.la/richard11209
:
e:
to
hat were really fast, high gain parts, and some comment to the effect that it was a 20-stage process, where regular processes were about 12 stages, bu t it was all from some Analog Devices presentation, and I haven't been to o ne for a decade or so.
nd analog parts and MEMS parts in-house, rather than relying on foundries, but nothing all that specific.
s fast as the state of the art stuff used for making advanced digital chips .
ion, and anyway ion implantation can offer you that rather more cheaply tha n optical techniques - and has been able to do that for ages. It's as slow as a wet week, so you can only have the high resolution at a few critical s pots on the device, which is probably all you need for something like the A D797
arts.
Which is to say that you couldn't see the relevance.
The AD797 does seem to use high gain fast PNP transistors, and ion implanta tion does seem to be the way that Analog Devices gets them. It probably wou ldn't be the kind of solution that would work for a digital array of millio ns of identical sets of transistors, but it's fine for this application.
-- Bill Sloman, Sydney
Analogue CMOS stopped getting better at about the 180-nm node, and was certainly going into the tank by 65 nm. At that resolution, you can use single-exposure DUV or excimer litho and regular chrome masks. That saves a lot of money.
Cheers
Phil Hobbs
-- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net http://hobbs-eo.com
Przemek Klosowski.... thank you for pointing to that interview on YouTube. I really liked the guys view on what the ltspice program is for which is so that the engineer can get better intuition as to how his circuits work. It is a piece of verification but should not be used is the sole purpose of v erifying. I guess I like it because it resonated with my viewpoints about u se of such a program
+1
Being an IC guy, he did miss that a little as regards PC boards. I often use LT Spice as the only process before I go to a PC board, but then PC boards can be modified a lot easier than linear ICs, and parts are mostly temperature stable as purchased.
And I design using LT Spice. Once one has some intuition, one can just throw parts around in the sim and see what happens. That works surprisingly well. I have several circuits in production that I don't really understand.
I do much less math than I used to do. I guess rough values and tweak in LT Spice. Voltage dividers, filters, oscillators this week. So it's a calculator, too.
It also draws presentable diagrams to include in emails and manuals. It's a drawing program.
I've had his same thought before: Romans built waterworks, people built bridges and cathedrals and cannons and sailing ships, before Newton invented calculus. Most science explained what people had already built.
-- John Larkin Highland Technology, Inc The cork popped merrily, and Lord Peter rose to his feet. "Bunter", he said, "I give you a toast. The triumph of Instinct over Reason"
I don't throw parts around. I design first and then see if my design in LTSpice shows something I overlooked. If it doesn't result in what I expected, I try to learn why and correct it.
Indeed. I do the same. Sometimes it is faster than using a calculator.
Agreed. I miss Mike.
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