Multi Bit Multiplexers & Addressing Notes | EduRev

Digital Electronics

Electrical Engineering (EE) : Multi Bit Multiplexers & Addressing Notes | EduRev

The document Multi Bit Multiplexers & Addressing Notes | EduRev is a part of the Electrical Engineering (EE) Course Digital Electronics.
All you need of Electrical Engineering (EE) at this link: Electrical Engineering (EE)


Multi−Bit Multiplexers

There are many uses for multiplexers. Wherever a number of signals, or logic states, need to be passed down a single communication channel such as a wire, a radio channel, or a telephone, some form of multiplexing is used. Sometimes the multiplexing and de-multiplexing can be very complex, much more so than the circuit in Figs 4.2.2 and 4.2.3. In some systems, data is transferred over very long distances, in others such as transferring data within computers, the distances may be very short. Fig. 4.2.4 shows a 4 to 1 line multiplexer, which enables a 4-bit binary number to be passed over 3 lines, one for data and two for control.

 

        Multi Bit Multiplexers & Addressing Notes | EduRev

 

 

Addressing

Larger multiplexers, such as 4, 8 or 16 bit types, which are readily available in IC form, use a method of ‘addressing’ a particular data gate using a binary code. Fig 4.2.4 shows a 4 to 1 multiplexer where, in order to output data from a particular input, one of the four 3−input NAND gates must be enabled by a logic 1 on two of its inputs, leaving the third input for data. To achieve this two address lines are used, giving four possible combinations of 1 and 0. Look carefully at the address lines. When both are at logic 0 the two inverters (NOT gates) produce logic 1s at two of the inputs to NAND gate 00. None of the other NAND gates addressed by these lines has both its address inputs at logic 1. If the least significant bit (lsb) of the address is 1 and the most significant bit (msb) is 0 then NAND gate 01 is enabled. Because two address lines can give four possible binary combinations, you should find that, counting from the top, gate 00 is enabled by the address inputs 002, gate 01 by address 012, gate 10 by 102 and gate 11 by 112.

 

Multiplexer IC Datasheets

There are many commercially available multiplexer ICs available with a variety of extra features. The following is a list of datasheets for some basic multiplexers similar to those described in this article.

 

74HC151 8 To 1 multiplexer from NXP

Multi Bit Multiplexers & Addressing Notes | EduRev

74HC153  4To 1 multiplexer from Texas instruments

Multi Bit Multiplexers & Addressing Notes | EduRev

74HC257 Quad 2input Multiplexer from NXP

Multi Bit Multiplexers & Addressing Notes | EduRev

74HC352Dual 4 to 1 Multiplexer from Texas instruments

Multi Bit Multiplexers & Addressing Notes | EduRev

 


Offer running on EduRev: Apply code STAYHOME200 to get INR 200 off on our premium plan EduRev Infinity!

Related Searches

Multi Bit Multiplexers & Addressing Notes | EduRev

,

Previous Year Questions with Solutions

,

MCQs

,

Semester Notes

,

pdf

,

practice quizzes

,

Summary

,

study material

,

Free

,

Extra Questions

,

Sample Paper

,

past year papers

,

Multi Bit Multiplexers & Addressing Notes | EduRev

,

Objective type Questions

,

Viva Questions

,

Exam

,

ppt

,

video lectures

,

shortcuts and tricks

,

mock tests for examination

,

Multi Bit Multiplexers & Addressing Notes | EduRev

,

Important questions

;