Cloning the ca3080
o...@uakron.edu
have a legacy design I may need to make thousands of...
What I mean by suggestions is if any of the IC designers here could
see any hidden process gotchas in the drawing in the datasheet. Ie
emitter width, hidden structures, etc...
And yes, I know about the 13700 series...
Steve
Tim Williams
thermal time constants) without monolithic construction. The representative
circuit seems to be current mirrors and a diff amp, which will work fine.
Doesn't seem to be anything remarkable about it, no bandgaps or Widlar-esque
craziness.
Tim
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<o...@uakron.edu> wrote in message
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Jim Thompson
We could make a copy ;-)
...Jim Thompson
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Bitrex
Probably fakes, but maybe...they're good fakes? :)
petrus bitbyter
<o...@uakron.edu> schreef in bericht
news:9db11a06-1382-48e5...@z11g2000yqz.googlegroups.com...
Digi-Key lists the CA3080E from Intersil though they seem to have no stock.
Though the design seems pretty simple, building a thing like that in
discretes may become a real nightmare.
If you really need thousends, ask Jim. He seems to have some experience with
that kind of designs :)
petrus bitbyter
Joerg
> Any suggestions before I start to clone the ca3080 in discretes? I
> have a legacy design I may need to make thousands of...
>
Wow, that was shortly after the era of nuvistors :-)
> What I mean by suggestions is if any of the IC designers here could
> see any hidden process gotchas in the drawing in the datasheet. Ie
> emitter width, hidden structures, etc...
>
> And yes, I know about the 13700 series...
>
You might want to call these guys and ask how many they are holding:
http://www.jdr.com/interact/item.asp?itemno=CA3080
And these guys:
http://www.questcomp.com/
Haven't dealt with either company lately and I don't know what the
difference between the A, M, non-dash or other versions might be. Why
does it absolutely have to be the CA3080?
--
Regards, Joerg
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Use another domain or send PM.
Bitrex
> o...@uakron.edu wrote:
>> Any suggestions before I start to clone the ca3080 in discretes? I
>> have a legacy design I may need to make thousands of...
>>
>
> Wow, that was shortly after the era of nuvistors :-)
>
>
>> What I mean by suggestions is if any of the IC designers here could
>> see any hidden process gotchas in the drawing in the datasheet. Ie
>> emitter width, hidden structures, etc...
>>
>> And yes, I know about the 13700 series...
>>
>
> You might want to call these guys and ask how many they are holding:
> http://www.jdr.com/interact/item.asp?itemno=CA3080
>
> And these guys:
> http://www.questcomp.com/
>
> Haven't dealt with either company lately and I don't know what the
> difference between the A, M, non-dash or other versions might be. Why
> does it absolutely have to be the CA3080?
>
I'm curious about the last point as well - as far as I know if one
doesn't use the linearizing diodes and output buffer for all intents and
purposes one half of an LM13700 is equivalent to a CA3080. According
to: http://www.idea2ic.com/LM13700.html the LM13700 prototype was
breadboarded with 3080s.
David Eather
> o...@uakron.edu wrote:
>> Any suggestions before I start to clone the ca3080 in discretes? I
>> have a legacy design I may need to make thousands of...
>>
>
> Wow, that was shortly after the era of nuvistors :-)
>
>
>> What I mean by suggestions is if any of the IC designers here could
>> see any hidden process gotchas in the drawing in the datasheet. Ie
>> emitter width, hidden structures, etc...
>>
>> And yes, I know about the 13700 series...
>>
>
> You might want to call these guys and ask how many they are holding:
> http://www.jdr.com/interact/item.asp?itemno=CA3080
>
> And these guys:
> http://www.questcomp.com/
>
> Haven't dealt with either company lately and I don't know what the
> difference between the A, M, non-dash or other versions might be. Why
> does it absolutely have to be the CA3080?
>
It makes nice voltage controlled filters
Joerg
Ok, it's a nifty chip, has bias control:
http://www.intersil.com/Data/fn/fn475.pdf
But can't one do most things as well with a Gilbert multiplier or a
gain-steerable video amp? If Steve wants to verbatim build another round
of a yesteryear design then I could see the need. But to obtain
thousands, that'll be slim pickings.
o...@uakron.edu
analog, sine wave VCOs, and 8038, 2206, and max38 are gone. Cost is a
factor and microprocessors are unwelcome for this application.
So I looked at the analog synth stuff , and 3080 has bandwidth to
spare...
Since this product may have to run for a decade, roll your own starts
to look good... But at estimated 5K a year its hard to justify a
foundry run.
Steve
JW
id: <570c6198-278b-4b26...@e6g2000yqh.googlegroups.com>:
Don't know what the pricing is, but these guys still make LM3080 and
CA3080s:
http://www.rocelec.com
Altogether they have over 80K pieces.
Stephan Goldstein
I used 3080s in a tunable formant filter for analog speech synthesis
about 30 years ago. It worked fine, but watch out for amplitude
scaling. Without the linearization diodes (LM13700) the 3080 is truly
a small-signal device, you'll start to pick up distortion with input
differentials less than kT/q.
We did try to make an "improved" version using the linearized
parts, but it sounded different and people didn't like it as much.
steveg
MooseFET
The CA3080 had the problem that the transconductance varies from unit
to
unit too much.
You can make about as good of a variable gain by using a JFET to
control
the gain of an amplifier. If you get one designed for voltage
controlled
resistor service, you may be better off:
http://www.linearsystems.com/products.html#GlossD
See VCR11N
If you use a dual you can use a little feedback circuit on one to make
the
right gate voltage for the other and get the resistance control to be
within about 20%.
Jim Thompson
You're going to have a helluva time getting the device
matching/tracking necessary.
What's the end use? Offline if you like.
hamilton
I just did a Google search and Google suggested "CA3080 replacement".
It would seem others have a need to replace this part as well.
With over 10,000 hits, there may be close some replacement out there.
hamilton
Joerg
Depends on how urgently it's needed in the marketplace and thus how much
customers are willing to plunk down. At 5k/year a custom chip would
cost serious two-digit, considering the amortization of IC design and
masks over 4-5 years.
I don't know why uC are ruled out because that would be the way to go
these days. Another option is to run an oscillator at a few hundred kHz
or a MHz where you can use varicaps, and then mix that down to audio.
whit3rd
> Depends on how urgently it's needed in the marketplace and thus how much
> customers are willing to plunk down. At 5k/year a custom chip would
> cost serious two-digit, considering the amortization of IC design and
> masks over 4-5 years.
That's SO extortionate! The CA3080 has five transistor pairs, no MOS
or multilayer metallization, no resistors, only handles a milliamp of
current...
What lame designer or design center would have to 'amortize the IC
design' over a period of years to handle this little item?
Aren't there semicustom routes, too?
o...@uakron.edu
my boss just to buy a 10 year supply. Goal was no RF noise for a
instrument app. I liked the linear, and the idea was to have to do as
little redesign as possible during production.
Steve
MooseFET
How about using an LT1228 to do the same sort of function?