[sdiy] matrix ICs

[Paul R. Higgins]

> I guess this means that video and audio are NOT interchangeable??? Biggest
> problem I can see for the average DIYer is that these devices are high pin
> count which means fine pitch SMDs - should be fun to solder. Also probably
> quite expensive but cheaper than a patch matrix panel and more elegant
> [IMHO].

Quite a few of the matrix ICs are manufactured in through-hole versions.  But 
the really big matrices from AD are only available in SMD packages (PLCC, etc.).
As for audio/video matrices and their interchangeability, I've had a look at the
datasheet for the Intersil matrix (HA456), and it looks like it _might_ work OK 
for audio.  I'm leaving the final determination on that to those who have used 
the part.  The HA456 is set up specifically for video, with high-current/speed 
line drivers. OTOH, that might be an added bonus for audio purposes.  However, 
the headroom doesn't look that great--max supply is 12V (rail-to-rail).

As for expense, a quick look at the various manufacturers' websites shows prices
which are pretty reasonable.  Plus, you should be able to get a couple as 
samples.  The eval boards from AD are a bit pricey for the hobbyist, however 
(about $400 US).

Does anyone know about the 8 x 8 matrix that's part of someone's HC/HCT CMOS 
line?  I thought I saw it once in a Digi-Key catalog.

-PRH


_____________________________________________
Paul Higgins
email: higg0008 at tc.umn.edu
University of Minnesota
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