[sdiy] FPAA for analog synthesis?

[ASSI]

On Wednesday 03 March 2010, Dave Manley wrote:
> The Array700 has what they call a 'junction capacitor' which are
> under some of the pads.  Are these not available in the
> Interdesign parts?

No, not in the monochip arrays.  You could use some actual junctions 
and the pinch resistors as capacitances, but it wouldn't amount to 
much.  There's clearly a development to be seen when you follow these 
parts from their origin, certainly triggered by feedback from 
customers and their own design experience.

> I presume the Interdesign arrays also have "cross unders" which
> helps to obscure the interconnect.

Not dedicated ones, but you can use the collectors of the npn and 
basis contacts of the pnp for that (and they've had to use it quite a 
bit).

> Back in the mid 80's I routed
> some single metal layer 3 to 5 micron gate arrays (they had a
> grand total of <5K gates :-) ), and the limited routing resources
> definitely made routing a challenge, forcing the use of a
> transistor gate as part of the route on occasion.

Exactly.  Takes a bit of getting used to, but you're not going to 
utilize every transistor anyway.

> BTW, I've never been able to track down the data books you
> reference on your web page.  Too bad there's not a pdf available
> anywhere...

I've been lucky on obtaining them used (or mostly unused, as they had 
none of the wear and tear I expected).  Took a while of hunting and 
the help of several people.  I've been sending mails to Hans Camenzind 
about these publications, but never got a response.  Even if he would 
have, I'm not sure he could clear the copyright by himself and who 
knows where those rights ended up finally... 


Achim.
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