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Some transistor models are very far from real behavior. Nobody checks that. What bothers me is that ADI violates the SPICE rule that model names must be unique. And nobody at ADI seems to care.

very much appreciated this warning. A useful community service... ________________________________ Sent: Saturday, July 8, 2023 5:18 AM To: [email protected] <[email protected]> Subject: Re: [LTspice]

Thank you for the explanation. Much appreciated.

Perhaps it's as well I'm a bit of a dog, then. -- Regards, Tony

Yes, I did mean 'will'. My (limited) experience is that even different data books don't give the same graphical data, and models are no different in that respect.? Yes, you can tweak a model, but

I say 'fictitious', because no such signal with that waveform was the input for the simulation.? I agree that the result of the inverse FFT is the impulse response (within limitations). There is

I presume you meant "It's unlikely that a model "will* produce curves that closely match those in the data sheet"? Of course that's not true. In many cases, you can tweak a model to almost overlay

John wrote, "... an inverse FFT will produce a (fictitious) waveform whose spectrum is the frequency response. I can't see much use for that. "? It might be useful to see the impulse response of your

The output from an .AC simulation is a high-resolution spectrum, so indeed an inverse FFT will produce a (fictitious) waveform whose spectrum is the frequency response. I can't see much use for that.

That's not a huge undershoot, not compared to the pulse itself.? The undershoot is -125 mV and it lasts for less than 10 ns.? If you made the I1 pulsewidth wide enough so that the op-amp's output

Hi Andy. Thank you for your feedback. When I mentioned that I was not seeing what I expected at the output of the TIA, I should have been more precise. I am not sure I understand why there is so much

Going back to this discussion adding another tidbit: If you run an .AC analysis, and then do a View > FFT, LTspice will gladly perform an (inverse) FFT on the frequency-domain output from the .AC

No doubt you can carry out an optimization, but it requires a deep knowledge of what each of the model's parameters determines, which is far from straightforward. It's unlikely that a model with

Good stuff. For accurate model assessment and optimisation, I also have a method of importing the datasheet data into LTspice for direct comparison. It's this latter bit that's onerous, because it

Fabulous guys. I had thought it might require me to write my own test setup but it's good to hear that these have been made available. I'm not talking about anything exotic here. I only mean BJTs,

What you say about this is true, hFE does have significant statistical spreads, but the datasheet limits are probably set at 3 sigma (any outside this being rejected, being only a 0.3% loss). 3 sigma

You put your device and its model into a curve-tracer .ASC and set it up to produce (if it will) the same curves as in the data sheet. Compare the results. You can find curve-tracer .ASCs by going to

I have searched for this and can't find anything that is generic and at my level but, is there somewhere information on a sensible validation procedure for the simple classes of model?? I mean

Christoph wrote, "Maybe there were meant to be time/value tuples in angle brackets and they were fallen victim to the HTML conversion?" I think they just got edited out or omitted by accident. Andy

That’s what I was initially thinking of (and also posted it). What you are mentioning is BNF (Backus-Naur form of descripion of higler level programming language syntax). Only I was missing the left