Proprietary SMPS design tools, what for?

Because most designers don't really have a clue about what they're doing, and don't want to. So spoon-feeding them super-safe circuits that are designed by a machine that's designed by some zit-faced kid in India will lead them to better success than trying to teach them basic principals.

(Note that LTSpice _is_ proprietary, and part of the reason the models for Linear parts work better in it is because they use the proprietary features of LTSpice, not 'regular' spice models which LTSpice can't use as fast as it's 'own' stuff).

Because in most companies marketing is an expense, not a profit center, and a proper SPICE circuit is 'too expensive'.

Why did Zilog spend 20 years driving away any designer who wasn't going to order 20000 parts at a whack? Because they're stupid! After they taught all those kids to shun them, they had to go and convince them (me amongst them) to use Zilog after all -- and I still won't.

When you say 'daft', your questions answer themselves.

Often it's easier to get an eval board (cage one for free!) and try it, with real caps and such. Load step transient response can tell you a lot about stability. Varying loads, including open/short, can tell you a lot too.

WebBench is a notorious dog. LT Spice is a gift to humanity.

John

Sure, but: I can use other companies' stuff and just accept a slower simulation speed because the sub-circuits become kind of hefty. Gets me to the goal line while those online calculators never did. I have yet to encounter a situation where LTSpice would reject a proper SPICE model of a non-LTC part.

And here I thought they had already gone belly-up :-)

:-)

Hey, the LTC area manager did just that. I butchered it up pretty badly but now I know it does what the sims say it's s'posed to. The butchering mostly happened because it was RoHS-soldered.

How true that is.

I'm amazed at the support the LT gives. Even for us little guys, we are given eval boards and lots of support from their field engineer. Plus, a decent way to simulate their switchers which I tend to use in unconventional ways that WebBench couldn't deal with. WebBench is so slow and limiting I gave up. The one National switcher controller I did use required doing a prototype board with a couple different configurations of the switcher. Fortunately, the overly simplified model of the NS part I created in LTspice was close enough to reality.

Our LT rep said most of LT's business is smaller companies.

Part of the issues is CHEAP-CHEAP. A few years ago I was approached by a major ANALOG company (you can guess who :-) to model a complex device. I figured about a week of my time to do it proper justice. Too expensive for them :-( ...Jim Thompson

LTs field engineering staff is saving my new job. We had a state of the art special buck switcher being custom made, and the supplier's marketing people dropped the ball and the project. It seems 3000 pieces per month is not worth a run to them. Two conference calls and a couple weeks later a LTspice model arrives with demo boards . LT didn't hesitate to sign our ND, either. I'm too busy doing the custom optics and control design to learn switchers from scratch right now.

A bit of wimping out on my part, but I have spent three months just trying to source parts for the rest of the system, and the boss wants a field worthy trial system in 30 days to replace my huge bench model.

Don't even try to manufacture anything in America any more, its a tough mess, and I need 60% US content for the contract.

Thank You, LT!

Steve

I completely agree with Tim here.

It's also the reason that you won't have any difficulty finding employment any time soon, Joerg. :-)

---Joel

Right now I'd already be happy if I had at least the Labor Day weekend off. Saturday may already be toast :-(

But we'll have a guide dog puppy here as sitters so we can't travel much anyhow.

Yep. LT isn't cheap but they have good stuff and excellent support. I was asking about a USB/Li-Po battery controller/regulator chip last week for a cost reduction I'm doing. By Monday I had a development kit in hand. The disty is having another multiple output regulator kit sent. Great service but as I said, the stuff isn't cheap.

I believe it. They really aren't in the ten-cent chip market. Also note that LT is making money.

Seems like they (LT) decided to solve the problem of creating models efficiently, rather than create bespoke models one at a time-- which is why they can claim to have more SMPS chip models than all the rest.

"I see no reason for the continuing existence of AMD "

-- Mike E.

I would imagine that the LT chip designer either creates the model himself, or works closely with the model creator. That's much easier than after the fact, being spoon-fed "declassified" data :-(

...Jim Thompson

Elaborating: The ideal way to make a _behavioral_ model is to start with a _device_level_ netlist, particularly if a back annotated (with strays) version can be had. Then it's just a matter of fitting behavioral functions.

Unfortunately foundries are _very_ unlikely to give an outsider a true netlist :-( ...Jim Thompson

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I can see at least one good reason to keep AMD, a sufficient thorn in Intel's side to keep them halfway honest. There may be more reasons.

AMD can make darn good processors. My laptop has a 64-bit Turion in there and while older that thing still gives newer machines at clients a run for their money when doing sims.

Best was a session where we did hands-on design on Cypress PSoC. About eight guys starting the compile at the same time. When I signaled mine was done a couple of guys across the table said "WHAT?". They had freaking expensive Thinkpads.

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Thinkpads, and laptops in general, aren't tuned for performance even if that's what the power manager says. You bitch about battery performance, yet want to bring it down to just enough time to boot. ;-)

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Nah, for battery performance I have a Samsung NC-10. Gets me 8h out of its standard battery. Don't even think about running SPICE on it's little Intel Atom processor. I did, once, and hit the stop button when I realized it was still at around 1% completion after 10 minutes.

The Durabook that has the AMD is one of those semi mil-spec laptops. It gets about 2h which is enough to make it through the typical design review. The good thing is that I can do CAD with it and run simulations while at clients, provided I took the AC adapter along.

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Full function laptops are designed to be sorta "good enough" when used as desktops or portable. They'll easily get blown away by last generation desktops on the performance end and special purpose "net books" in the battery department. Each laptop puts the design point in a different place though. IOW, it's not surprising that a ThinkPad sucked as a cycle server. ;-)

Yep, the power/performance dial turned the other way.

Ok, but what is it good at then? Considering that guys paid even more for their Thinkpads than I did for my Durabook. Battery runtimes are similar.