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Binary to decimal decoder with open collector outputs?

Started by bitrex October 20, 2015
Did anyone make a 74** something or other that was a binary to 
one-of-ten decoder that had open collector/drain outputs that one could 
wired-OR together?

I need to take a binary coded output from a logic IC that's in the 1 to 
10 range and convert it to a single on/off decimal output in the range 
of 1 to 5. Maybe there's a better way to do this.
bitrex wrote:

> Did anyone make a 74** something or other that was a binary to > one-of-ten decoder that had open collector/drain outputs that one could > wired-OR together? > > I need to take a binary coded output from a logic IC that's in the 1 to > 10 range and convert it to a single on/off decimal output in the range > of 1 to 5. Maybe there's a better way to do this.
Yes, 74 (LS) 145. Jon
On Tue, 20 Oct 2015 14:23:35 -0500, Jon Elson <jmelson@wustl.edu>
wrote:

>bitrex wrote: > >> Did anyone make a 74** something or other that was a binary to >> one-of-ten decoder that had open collector/drain outputs that one could >> wired-OR together? >> >> I need to take a binary coded output from a logic IC that's in the 1 to >> 10 range and convert it to a single on/off decimal output in the range >> of 1 to 5. Maybe there's a better way to do this. >Yes, 74 (LS) 145. > >Jon
There's also the 7441 high voltage (nixie driver) part. -- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
On 10/20/2015 3:23 PM, Jon Elson wrote:
> bitrex wrote: > >> Did anyone make a 74** something or other that was a binary to >> one-of-ten decoder that had open collector/drain outputs that one could >> wired-OR together? >> >> I need to take a binary coded output from a logic IC that's in the 1 to >> 10 range and convert it to a single on/off decimal output in the range >> of 1 to 5. Maybe there's a better way to do this. > Yes, 74 (LS) 145. > > Jon >
Great, I'd forgotten about that one. Thanks!
bitrex wrote:
> Did anyone make a 74** something or other that was a binary to > one-of-ten decoder that had open collector/drain outputs that one could > wired-OR together? > > I need to take a binary coded output from a logic IC that's in the 1 to > 10 range and convert it to a single on/off decimal output in the range > of 1 to 5. Maybe there's a better way to do this.
TI or (old) Fairchild.
bitrex wrote:

> On 10/20/2015 3:23 PM, Jon Elson wrote: >> bitrex wrote: >> >>> Did anyone make a 74** something or other that was a binary to >>> one-of-ten decoder that had open collector/drain outputs that one could >>> wired-OR together? >>> >>> I need to take a binary coded output from a logic IC that's in the 1 to >>> 10 range and convert it to a single on/off decimal output in the range >>> of 1 to 5. Maybe there's a better way to do this. >> Yes, 74 (LS) 145. >> >> Jon >> > > Great, I'd forgotten about that one. Thanks!
Oh, and the outputs would be wire-ANDed, if you used them in the positive- logic sense. But, since they are active-low, I guess you end up with a wire-NOR output, actually. Jon
Jon Elson <elson@pico-systems.com> Wrote in message:
> bitrex wrote: > >> On 10/20/2015 3:23 PM, Jon Elson wrote: >>> bitrex wrote: >>> >>>> Did anyone make a 74** something or other that was a binary to >>>> one-of-ten decoder that had open collector/drain outputs that one could >>>> wired-OR together? >>>> >>>> I need to take a binary coded output from a logic IC that's in the 1 to >>>> 10 range and convert it to a single on/off decimal output in the range >>>> of 1 to 5. Maybe there's a better way to do this. >>> Yes, 74 (LS) 145. >>> >>> Jon >>> >> >> Great, I'd forgotten about that one. Thanks! > Oh, and the outputs would be wire-ANDed, if you used them in the positive- > logic sense. But, since they are active-low, I guess you end up with a > wire-NOR output, actually. > > Jon >
Just to be clear, on the '145 if I input a binary '1' say, then that turns on the output transistor corresponding to decimal 1' on and pulls down on the common resistors? -- ----Android NewsGroup Reader---- http://usenet.sinaapp.com/
bitrex wrote:


> Just to be clear, on the '145 if I input a binary '1' say, then > that turns on the output transistor corresponding to decimal 1' > on and pulls down on the common resistors? > >
I think so. I now use Digi-Key as my default shelf of data books. (I think I send them PLENTY of money each year, so they shouldn't mind!) Basically, any semi you can think of, they will have the datasheet available on the page where they list the prices. Way faster than getting up and going to the shelf. I looked up the 74145 to answer your original question. The data sheet had a gate-level schematic and a truth table. Jon
On Wednesday, October 21, 2015 at 9:53:05 AM UTC-7, bitrex wrote:

> >>>> I need to take a binary coded output from a logic IC that's in the 1 to > >>>> 10 range and convert it to a single on/off decimal output in the range > >>>> of 1 to 5.
> Just to be clear, on the '145 if I input a binary '1' say, then > that turns on the output transistor corresponding to decimal 1' > on and pulls down on the common resistors?
None of this is clear to me, but the '145 is a legacy part, I'd want to avoid using it. It produces a different single LOW output for each of the 1 to 10 inputs, if that's what you want. A 74HC138 can often do the same task, but it has only eight outputs (you said "1 to 5" for the output). Any 74xx138 has three enable and three address inputs, many four-bit input combinations can be decoded, your combination might be one.