Multiplexers

Discussion in 'Homework Help' started by lolmlol, Oct 12, 2013.

  1. lolmlol

    Thread Starter New Member

    Oct 12, 2013
    4
    0
    I want to make 8:1 mux using two 4:1 mux. practically. I want to make it using both, gates and multiplexer i.c. Please help me out soon.
     
  2. MrChips

    Moderator

    Oct 2, 2009
    12,414
    3,353
    How soon? I'm gonna go pick some apples.
     
    absf and tshuck like this.
  3. ScottWang

    Moderator

    Aug 23, 2012
    4,848
    767
    Go check CD4000 series or 74HC4000 series or google Multiplexer
     
    lolmlol likes this.
  4. tshuck

    Well-Known Member

    Oct 18, 2012
    3,531
    675
    Well, considering this is Homework Help you should start h\by stating what you need help on - note the difference between helping you and doing it for you (which we won't be doing).

    Show us your work and a thought process and we will try to help you.

    Is there a specific mux, or just one in general?
     
  5. WBahn

    Moderator

    Mar 31, 2012
    17,715
    4,788
    Is there a question in this? What is it that you would like help on? And how soon?

    What do you consider to qualify as "practically"? Most people wouldn't consider making an 8:1 MUX using gates to be a very practical thing to do.

    Which 4:1 MUX do you have in mind?
     
    lolmlol likes this.
  6. lolmlol

    Thread Starter New Member

    Oct 12, 2013
    4
    0

    Can we make 8:1 using 74LS153???
    I don't hav much knowledge about MUX IC's.
     
  7. WBahn

    Moderator

    Mar 31, 2012
    17,715
    4,788
    No, the '153 doesn't consist of independent 4:1 MUXes, the two MUXes share the same select bits.

    Instead of worrying about a particular chip, let's focus on a generic, no-frill, basic 4:1 MUX. We need to make sure that you understand your starting point.

    What does a basic 4:1 MUX consist of? What are the inputs, what are the outputs, and how to the outputs relate to the inputs?
     
    anhnha likes this.
  8. lolmlol

    Thread Starter New Member

    Oct 12, 2013
    4
    0
    Yeah, i know the basics... a 4:1 MUX consist of 4 inputs, 2 selection channel and 1 o/p.
    whereas a 8:1 MUX consist of * i/p, 3 selection channel and 1 o/p... right??
     
  9. ScottWang

    Moderator

    Aug 23, 2012
    4,848
    767
    There are two ways to solve your problem, the one is to make the function using logic IC, you can google 4 to 1 multiplexer then you can get a lots of infos.

    The other one is as following, but I'm not sure you can buy the IC or not:

    FST3253 - Dual 4:1 Multiplexer/Demultiplexer Bus Switch.

    SN74HC4852-Q1 - DUAL 4-TO-1 CHANNEL ANALOG MULTIPLEXER/DEMULTIPLEXER WITH INJECTION-CURRENT EFFECT CONTROL.
     
  10. Alec_t

    AAC Fanatic!

    Sep 17, 2013
    5,764
    1,099
    If you are going to use two 4-bit mux to make an 8-bit one, consider how you are going to select/combine their outputs.
     
  11. mghg13

    Member

    Jul 17, 2013
    63
    0
    hi,

    I came across this type of mux expansion recently. I think you should make use of the enable lines. See the image for a circuit. I'm not sure if it is correct. verify with senior members
     
  12. WBahn

    Moderator

    Mar 31, 2012
    17,715
    4,788
    The main thing I asked for was the relationship between the inputs and outputs. After all, I can make lots of chips with six inputs and one output that are NOT a 4:1 MUX. But I'll just assume that you understand these relationships.

    If you have 8 signals and 3 select lines, is it possible to group them into two sets of 4 signals having a shared pair of select lines and then use the third select line to choose between the two sets?

    How might you go about that?
     
Loading...