At 04:02 PM 11/16/2005 +0000, you wrote:
> >Has anyone ever had a product done that has used
> >( i think) leadless chips...the lil blobs of epoxy
> >over the part that gets mounted directly to the board....
>
>You mean Chip On Board (COB) as used in greetings cards etc.
>
>Never used it, but guess that the failure rate could be potentially great as
>one would be buying the chips to fit to the boards with a bonding machine.
>Personally I would suspect that some of the tiny Bump Grid Array type
>devices would be the way to go if you can get them.

COB works best in consumer products with one or two chips on a board
than can be thrown away if it doesn't pass tests (few other parts, and no
expensive ones).

The savings are pennies (if that, and that assumes that the semi manufacturer
wants to sell the chips in die form, and prices them accordingly). Quantities
have to be fairly high, though less so if you've got a presence in Asia.

In fairly high quantity, we found a 40-pin *DIP* on a punched single-sided
paper based phenolic board to be a better design decision than a COB.

Best regards,

Spehro Pefhany --"it's the network..."            "The Journey is the reward"
speff@interlog.com             Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com
->> Inexpensive test equipment & parts http://search.ebay.com/_W0QQsassZspeff


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