LTSpice LED parameters

Is changes the ideal-diode (exponential) part of the curve, and Rs changes the linear, ohmic part. LEDs get more linear, ohmic, at high currents.

Just fiddle until the simulated E:I curve matches your real part. You'll get a feel for that pretty fast.

Iave, Vpk and "type" are NOT true Spice parameters... they are toyLTspice fudges that use LTspice-specific models that are NOT usable anywhere else.

Toss those parameters completely,

Set Solver=Alternate

Tweak IS, Rs, N and EG to curve fit to your data.

For serious work, invest in a real simulator ;-) ...Jim Thompson

In message , John Larkin writes

N affects the slope of the exponential. M and VJ the capacitance. He might want EG as well.

Like pspice encryption?

Board level models are so buggy in general that a bigger flyswatter just makes a bigger mess.

Cheers

Phil Hobbs

Those are basically comments; they don't affect the sims.

Comments are nice. Don't you want to know part numbers?

LT Spice is wonderful, and free, and is getting a lot of kids interested in electronics. Why are you so hostile?

It's not the same thing. LTspice has encryption too, you twit.

.MODEL D D(...) is a standard device model format that will "play" on any other Spice-compliant simulator. Mikey's version will not.

The proper way to handle such a model is to define it as a subcircuit with parameter-passing.

Most LTspice models of their standard products won't "play" on any other simulator. Is that good business?

TI seems to have (somewhat) caught on to the fact that they need to offer across-platform/simulator models.

Wonder when Analog Devices (nee Linear) will catch on, toss Mikey, and make available compliant models?

I doubt that it's long coming. The LTspice List is now consumed by questions about what LTspice doesn't do right, hangs or crashes.

Baloney makes your head swell bigger ;-)

...Jim Thompson

LT Spice is free! It doesn't need to be "good business" in the paid-for simulator market. What it does is sell LTC chips.

I was told that ADI will be migrating to LT Spice. I think that LT Spice is one reason they bought LTC.

It works perfectly for me, no hangs or crashes. I did manage to crash it once some years back, by typing a very mal-formed illegal math expression. Mike fixed that in one day.

My, you are in a nasty mood lately.

He's still making payments on his Pspice license. ;)

Cheers

Phil Hobbs

Nope. I stopped paying "maintenance" when OrCAD/Cadence tried to neuter PSpice... about 12 years ago.

Two fortunate events:

(1) PSpice is INI-file controlled, thus removed features were trivial to put back.

(2) I was heavily involved with MicroSim clear back in the early days of development/debug... I probably led the pack in bug reports. Thus they provided me with a permanent/portable license ;-)

One of _many_ ways to curve-fit an LED can be found at

(That model will run on _any_ Spice simulator.)

Question for you bloviators... Suppose Apple is buying LTspice parts for their phones. Do you think that Apple has to run simulations on LTspice... or is Linear providing Apple with Cadence-level models? I'd bet the latter.

If you think the _big_ guys (and that's NOT Larkin or Hobbs) are running simulations on LTspice, I have some beach-front property in Yuma I'd like to sell you ;-) ...Jim Thompson

"Jim Thompson" wrote in message news: snipped-for-privacy@4ax.com...

Why would they buy overpriced LT parts when TI, Rohm or $Chinese is half price or less?

Tim

Good point. I've been involved with several companies (Synaptics for one) that design display systems/touch screens and their _numerous_ power supplies for "smart" phones.

You know, I can't recall ever seeing an LT part. ...Jim Thompson

Some of their parts are really good. LT1124. LTC3803. LTC2242. Their stuff is worth it when performance sells a product.

And sometimes just having a model and an example circuit sim is enough to sell a part. A day of my time can buy a lot of parts.

I understand that TI is migrating to PSpice.

I think you'll find that after the ADI acquisition, this will change. At least that's what they're telling me. ;-)

At low volumes, perhaps. TI outsells LT at CPOE by 1000:1.

Well, TINA is such a mess (the free version at least) that if they weren't bailing out they'd be morons.

Cheers

Phil Hobbs

Giving up TINA? I hadn't heard that. But, of what I've analyzed, TINA does not deviate enough from standard Spice to call home about. ...Jim Thompson

It's useful but not very. The paid version isn't any better, though it does allow imported models (PITA but it sorta works).

I think the Hittite part prices are a lot more sensible now that ADI acquired them.