66745

Multiplexer

A Multiplexer (MUX) is a Circuit that is used to direct one out of 2n inputs to a single output. It is

also called Data Selector because n-input select lines are used to select one of the input signals

and direct it to the output. A błock diagram of 4-to-l linę Multiplexer with

enable input is shown in

Fig. 1 and truth table for it in Fig. 2.

Since the enable input EN has negation symbol at its input in the błock diagram, 0 enables device

and 1 disables the device. Since the output linę has no negation symbol, when the device is

disabled, the output signal DO is 0. When the device is enabled, the device output signal DO

follows the data input signal selected by select lines Sil and SIO. Fig. 3 shows the functional logie

diagram for 4-to-l MUX with enable input.

Smaller Multiplexers can be connected together to obtain larger configuration. Fig. 4 illustrates in

błock diagram form how five 4-to-l Multiplexers can be connected to obtain 16-to-l Multiplexer.