[SOLVED] 16-to-4 multiplexer IC

[peak@eda]

Hello,

I'm in search of a multiplexer that allows me to input 16 digital lines and get a 4-bit digital output. The closest I've come is a 74LS151, 8 inputs and 1 output.

Any suggestions?

Regards
Peter

 

[barry]

This doesn't exist. You've got 65536 input states, but only 16 output states, how do you expect this to work? Do you have a truth table in mind?

 

[1/2dime]

2x 74xx147 or 148 ? E

 

[peak@eda]

barry,

Thanks for your reply and to clarify my poor explanation. I have 16 switches (on or off, high or low) I want to reduce the number of inputs to four by coding their input into 4 bits, thus 16 possible combinations, 0-15. Note: Only one switch is active at one time.

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Thanks ½ dime, I'm into that if no other solution will show.

 

[barry]

Ok, as long as you can ensure that one and only one input is active at a time. Could you use a small PLD like a Xilinx Coolrunner?

 

[jamespond]

74ls150 x 4
16 line to 1 line with 4 input selector and a gate signal.
Sorry, this is a "hard to find" part.

 

[peak@eda]

Ok, I'll go for the 151, thanks all !

 

[barry]

Ok, I'll go for the 151, thanks all !

That will totally NOT do what you want. The 151 is a data selector: the 4-bit selector input determines which of 16 inputs appears on its single output. It is not 4 outputs as your original post requested.

 

[jamespond]

You want to build something like this?
Or a 16 signal to 4 signal coder?

 

[barry]

You want to build something like this?
Or a 16 signal to 4 signal coder?
View attachment 93711

I think what the OP wants is to generate a 4-bit code depending which of sixteen inputs is (exclusively) active. The closest device to this is a priority encoder. But it would be a simple task for a PLD.

 

[fridadm]

Harris HD0165