How many enable line are available in 2-to-4 line decoder?

The SN74HC139 device comprises two individual 2-line to 4-line decoders in a single package. The active-low enable (G) input can be used as a data line in demultiplexing applications. This decoder/demultiplexer features fully buffered inputs, each of which represents only one normalized load to its driving circuit.

Does decoder have enable?

A standard decoder typically has an additional input called Enable. Output is only generated when the Enable input has value 1; otherwise, all outputs are 0. Only a small change in the implementation is required: the Enable input is fed into the AND gates which produce the outputs.

How does a 2-to-4 line decoder work?

This simple example above of a 2-to-4 line binary decoder consists of an array of four AND gates. The 2 binary inputs labelled A and B are decoded into one of 4 outputs, hence the description of 2-to-4 binary decoder. Each output represents one of the miniterms of the 2 input variables, (each output = a miniterm).

What is the minimum number of 2-to-4 decoders with enable inputs are required to implement a 4 to 16 decoder?

Originally Answered: How make a 4*16 decoder by using four of 2*4 decoders? If we are really talking about 74139 style 2 line to 4 line decoders you need 5 of them. Four provide the 16 outputs and the fifth one selects which of the first 4 is active.

How many gates are needed to construct a 2 to 4 line decoder?

We can implement these four product terms by using four AND gates having three inputs each & two inverters. The circuit diagram of 2 to 4 decoder is shown in the following figure. Therefore, the outputs of 2 to 4 decoder are nothing but the min terms of two input variables A1 & A0, when enable, E is equal to one.

How many outputs are on a BCD decoder?

ten output bits
A BCD to decimal decoder has ten output bits. It accepts an input value consisting of a binary-coded decimal integer value and activates one specific, unique output for every input value in the range [0,9].

How many inputs are needed for a 16 decoder?

Explanation: A binary decoder is a combinational logic circuit which decodes binary information from n-inputs to a maximum of 2n outputs. Here, number of outputs = 16. 16 = 24 = 2n. Thus, number of inputs is 4.

Which logic gates are needed to create a 2 to 4 decoder?

The basic building block of this decoder is shown in Fig. 3. The first-stage of 2-to-4 decoder requires four 2-input AND gates, because total number of logic combinations, that can be formed with two variables is four. Each logical combination of two variables A & B are given to input ports of respective AND gates.

What is a 4-to-1 multiplexer?

A 4-to-1 multiplexer consists four data input lines as D0 to D3, two select lines as S0 and S1 and a single output line Y. The select lines S0 and S1 select one of the four input lines to connect the output line.

How many 2 * 4 decoders are needed to design a 4 * 16 line decoder?

Therefore, we require two 3 to 8 decoders for implementing one 4 to 16 decoder.

How to build 4 to 16 decoder using only two 2 to 4 decoders?

Which line is 1 depends on the input bit pair which can be 00, 01, 10, 11. So take two such 2 -by- 4 decoders which give you four input lines. Let the output lines be a 0, a 1, a 2, a 3 for one decoder and b 0, b 1, b 2, b 3 for the other. Use the 16 AND gates to compute the 16 functions a i ∧ b j, 0 ≤ i ≤ 3, 0 ≤ j ≤ 3.

How to design of 2 to 4 line decoder circuit?

Designing of 2 to 4 Line Decoder Circuit Similar to the multiplexer circuit, the decoder is not restricted to a particular address line, and thus can have more than two outputs (with two, three, or four address lines). The decoder circuit can decode a 2, 3, or 4-bit binary number, or can decode up to 4, 8, or 16 time-multiplexed signals.

How to diagram a 3 to 8 decoder block?

The block diagram of 3 to 8 decoder using 2 to 4 decoders is shown in the following figure. The parallel inputs A 1 & A 0 are applied to each 2 to 4 decoder. The complement of input A 2 is connected to Enable, E of lower 2 to 4 decoder in order to get the outputs, Y 3 to Y 0. These are the lower four min terms.

How are parallel inputs applied to a decoder?

The parallel inputs A 1 & A 0 are applied to each 2 to 4 decoder. The complement of input A 2 is connected to Enable, E of lower 2 to 4 decoder in order to get the outputs, Y 3 to Y 0. These are the lower four min terms. The input, A 2 is directly connected to Enable, E of upper 2 to 4 decoder in order to get the outputs, Y 7 to Y 4.