Multiplexers and Demultiplexers.

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Multiplexer and Demultiplexer

• CEC

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Contents

• Multiplexer.
• 4 x 1 Multiplexer using Logic Gates.
• Demultiplexer.
• 1 x 4 Demultiplexer using Logic Gates.
• IC 74151 Pin out and Truth Table.
• Circuits using IC 74151.
• IC 74154 Pin out and Truth Table.
• IC 74138 Pin out and Truth Table.

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Multiplexer

• Many to One Circuit.

I0
I1
Y
Inputs
Output
I2
I3
Permits sharing of a common transmission medium,
efficient exploitation of available bandwidth
Parallel to Serial Conversion
S1
S0
Select Lines
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4 to 1 Multiplexer using Logic Gates
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Demultiplexer
One to Many Circuit.
Y0

Y1
D
Input
Outputs
Y2
Y3
Serial to Parallel Conversion
A
B
Select Lines
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1 to 4 Demultiplexer using Logic Gates
Select Lines
Input
Outputs
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8 x 1 Multiplexer

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IC 74151 Pin out

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Full Adder Using IC 74151
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Full Adder Using IC 74151
SUM
CARRY
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Design using a MUX Table
Data Input (D)
LSB
Y ?m(2,4,5,7,10,14)

ABC
Select
16 x 1 MUX using IC 74151 8 x 1 MUX
MSB
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Demultiplexer vs Decoder

• Decoder a certain case of a demultiplexer.
• Decoder is a demultiplexer without data input
  stream.
• Decoder to decrypt the input streams from one
  format into another.
• Demultiplexer to route information from a data
  input line to any of the multiple output lines.

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IC 74154 4-Line to 16-Line Decoder/Demultiplexer

• Decodes 4 binary-coded inputs into one of 16
  mutually exclusive outputs.
• Both the strobe inputs to be LOW.
• Demultiplexes by distributing data from one input
  line to any one of 16 outputs.
• Passes data from one of the strobe inputs with
  the other strobe input LOW.
• When either strobe input is HIGH, all outputs are
  HIGH.  

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IC 74154 Functional Diagram

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IC 74154 4 to 16 DemultiplexerPin out

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IC 74154 Truth Table

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IC 74154 Applications.

• In demultiplexing applications such as
• - digital clocks.
• - LED matrices and other graphical
• outputs.
• Multiplies the number of select lines 4 times to
  choose upto 16 devices/chips.

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IC 74138 Pin out

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IC 74138

3 inputs, 8 outputs
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IC 74138 - Three to Eight Decoder

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IC 74138 Logic Diagram

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IC 74138 3 x 8 Decoder

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Procedure
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MUX and DeMUX for Communication

Transmitter Side
Receiver Side
Shared Transmission Medium

MUX
DEMUX
IN
OUT
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Online Resources

• https//www.youtube.com/watch?vZQbdvHjXRwY
• https//www.youtube.com/watch?vM4JnENLKbi8
• https//www.youtube.com/watch?vHcO0LNr4UEI
• https//www.youtube.com/watch?vehetG6uN54U
• https//www.slideshare.net/CKSunith1/csl-202-multi
  plexer-and-demultiplexer

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Thank You