[sdiy] Effect of unconnected linearisation diodes in LM13600/13700

[Neil Johnson]

Andre Majorel wrote:
> ASSI wrote:
>
>> Even if Rochester has the masks, they are mostly useless since
>> the reason for EOLing the CA3080 was that the line that
>> produced them is no longer available.  It appears that plenty
>> of wafers were pre-produced however, so they can probably work
>> off that stockpile for quite some time.
>
> I thought that Rochester's mode of operation was precisely to
> keep obsolete fab processes running ?

I've been reading Rochester's website.  I think it needs careful
reading, with a big dose of context, and a side of economics.

As I understand it, Rochester cover the full range of processes for
supplying EOLed chips.  At the low end you have the simple case of
buying up remaining wafers, and using them up as customers buy them,
which may require slicing, testing, packaging.  That is the low end,
and likely where you'll continue to be able to get CA3080s at
realistic prices.

Then, up at the higher end, when there are no more die available, they
can recreate the required silicon, either by using existing fab
equipment and/or facilities where available, or reverse-engineering
the silicon, or starting from the original IP that they acquired from
the original source through the deals they strike.

On their website they mention the defence/military/aerospace words
many times.  Because that's the target market for this kind of
high-value service.  Any sensible commercial entity would simply
redesign their products to get around EOLed parts, it's the only
option that makes profitable sense.  The military, on the other hand,
have such huge development costs that it often works out cheaper to
pay for small batch custom silicon production, even if the end result
is each part costs $1000 and they only buy 100 of them.  Much much
cheaper than redesigning something that would cost $Millions (because
it is not only the redesign, but the re-verification, trial re-runs,
extensive testing, quality audits, etc etc etc...).

As far as our tiny little synthesizer world is concerned, we're at the
bottom of the ladder.

Cheers,
Neil
--
http://www.njohnson.co.uk