do 16-input nand gates exist?

[panfilero]

I've been looking on digikey and on mouser and I can't find them...
but does anyone know if 16input nand gates exist, and if they do,
where I can get some?

thanks!

 

[Chris]

I've been looking on digikey and on mouser and I can't find them...
but does anyone know if 16input nand gates exist, and if they do,
where I can get some?

thanks!

You can tie your 16 logic inputs to the 16 input pins of two ea. 2 X 4-
input AND gate ICs like the 74HC21. Those 4 outputs can then be
NANDed together by tying those 4 outputs to the 4 input pins of a 4-
input NAND gate, available as the 74HC20 (2 gates per IC). That
output is the logical equivalent of NANDing all 16 of your inputs. If
any of your 16 inputs go low, your output will go high.

Simple combinational logic can give you a workable solution from
standard logic ICs you can get off the shelf. Two real 14-pin ICs
instead of the one ideal but non-existent 20-pin IC.



Good luck
Chris

 

[Jamie]

I've been looking on digikey and on mouser and I can't find them...
but does anyone know if 16input nand gates exist, and if they do,
where I can get some?

thanks!

Use 2, 8 input types that drive a AND type..
74xx30
54xx30
XX = HC,HCT, LS etc..

Pick your poison.

http://webpages.charter.net/jamie_5"

 

[whit3rd]

I've been looking on digikey and on mouser and I can't find them...
but does anyone know if 16input nand gates exist,

They used to exist (one gate delay and sixteen NAND inputs),
in the form of TTL "expandable gates"; SN7423, SN7455, SN7460
and such. You would use an output (OR-INVERT section) with
any number of input expanders (AND sections), to make a composite
AND-OR-INVERT gate that had the same gate delay as a NAND or NOR.
To make a 16-input NAND, use two SN7460 expanders and a
single section of SN7423.

The signal from the expanders to the output section wasn't TTL-level,
though.

 

[MooseFET]

1. They do not exist.

2. Try this: (View in Courier)

Modified to save one part:

.Vcc>-------------+
.                 <---- delete
.                 resistor
.                    | \
.IN1>----[<CR1]---+---O|  >--->OUT
.                 |    | /
.                 .
.                 .
.                 .
.                 |
.IN15>---[<CR15]--+

. ! <--- change to resistor at IN16
.IN16>---[R]------



The circuit will be slow because of all the diode capacitances.

 

[JeffM]

MooseFET wrote:
http://groups.google.com/group/sci.electronics.basics/msg/4481f9b6cfd22d9d?dmode=source
(Look at what you have allowed Google to do to the whitespace.)

The solution:
http://groups.google.com/group/sci....oting+other.people's.sigs+weird-looking.posts