Re: Do any octal 3 to 8 demultiplexers exist?

On Tue, 03 May 2005 14:25:35 +0000, Michael Noone wrote:
> Keith Williams <krw@xxxxxxxxxx> wrote in
>> In article <Xns964B4252C07Emnooneuiucedu127001@xxxxxxxxxxxxxx>,
>> mnoone.uiuc.edu@xxxxxxxxx says...
>>> Hi - I'm looking for an octal 3-8 demultiplexer. Does such a beast
>>> even exist? If not (which I suspect) - are there any duals or quads?
....
>> That be a lot of pins (91 I/O, at least)! An FPGA would be a
>> possibility, though perhaps an expensive one.
....
> Yes it sure would be, and even more pins if I have to use 8 individual
> chips! I should mention though, that I only need a chip with common
> control lines - so really the ideal chip would only have 8 + 64 + 3 + 2
> = 77 pins (input, output, control, power). Honestly though I realize

So, do you want eight independent one-of-eights, or a one-of-64?
You could do that with 4X 74HC154, 4-to-16 decoder. That at least
reduces your chip count by half, albiet it's still 96 pins. And,
of course, you still have to select only one of them with a 2-to-4,
like a 74HC139.
http://www.standardics.philips.com/products/decoders/

Good Luck!
Rich

.

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