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On 7/06/2024 11:24 pm, legg wrote:On Fri, 7 Jun 2024 14:03:16 +1000, Bill Sloman <bill.sloman@ieee.org>>
wrote:
On 7/06/2024 4:05 am, legg wrote:On Thu, 6 Jun 2024 23:18:12 +1000, Bill Sloman <bill.sloman@ieee.org>
wrote:
>On 6/06/2024 1:46 pm, legg wrote:
<snip>
>That's sort of what I'm talking about. You choose a part, you choose a>
model, you choose a parameter that allows a model to simulate
performance more accurately. You choose a circuit configuration
with component values.
You mostly can't chose an EBIC model because the manufacturers treat
them as "commercial in confidence".
>
Gummel-Poon isn't as good, but it's mostly adequate.
>From the larger spreadsheet, you see models for 'similar devices>
varying widely in performance in a particular circuit configuration.
So what is it, in the model, or in the circuit configuration, that
allows such a wide variation in performance. What parameter is a
true predictor? What weakness in the circuit is the wild card?
Silly question. Gummel-Poon doesn't model inverted bipolar transistor
operation particularly well, but if you want anything else you will have
measure the device parameters for yourself, and nobody here has ever
claimed to have done that.
>Looking for understanding or beneficial increase in knowledge here.>
Not pushing or pulling the benefits or disadvantages of modeling
or breadboarding - already have pretty fixed opinions about that.
Do try to understand what practical circuit designers actually do.
>
I've never seen anybody set up a "spreadsheet" of transistor models.
>
The process is mostly working out what you can do with what you can get.
>
The models aren't perfect, and individual devices aren't identical, so
coping with production variation is part of the job. Some parts are
sorted by the manufacturer after production, which gives you
funny-looking parameter distributions.
>
--
Bill Sloman, Sydney
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