Circuit Design of 4 to 16 Decoder Using 3 to 8 Decoder

A decoder is a combinational circuit constructed with logic gates. It is the reverse of the encoder. A decoder circuit is used to transform a set of digital input signals into an equivalent decimal code of its output. For ‘n’ inputs a decoder gives 2^n outputs. In this article, we will discuss on 4 to 16 decoder circuit design using 3 to 8 decoder.

An encoder is a combinational circuit that changes a set of signals into a code. For ‘2^n’ inputs an encoder circuit gives ‘n’ outputs.


The following figure shows the block diagram of a decoder.

Decoder Block Diagram
Decoder Block Diagram

3 to 8 Decoder

This decoder circuit gives 8 logic outputs for 3 inputs. The circuit is designed with AND and NAND combinations. It takes 3 binary inputs and activates one of the eight outputs.

3 to 8 Decoder Block Diagram
3 to 8 Decoder Block Diagram

Circuit Diagram

The decoder circuit works only when the Enable pin is high.

3 to 8 Decoder Circuit
3 to 8 Decoder Circuit

Truth Table

When the Enable (E) pin is low, all the output pins are low.

PCBWay

S0S1S2ED0D1D2D3D4D5D6D7
xxx000000000
000100000001
001100000010
010100000100
011100001000
100100010000
101100100000
110101000000
111110000000

Circuit Design of 4 to 16 Decoder Using 3 to 8 Decoder

A decoder circuit of the higher combination is obtained by adding two or more lower combinational circuits. 4 to 16 decoder circuit is obtained from two 3 to 8 decoder circuits or three 2 to 4 decoder circuits.

When two 3 to 8 Decoder circuits are combined the enable pin acts as the input for both the decoders. When enable pin is high at one 3 to 8 decoder circuits then it is low at another 3 to 8 decoder circuit.

Truth Table

The Enable (E) pin acts as one of the input pins for both 3 to 8 decoder circuits.

EABCY0Y1Y2Y3Y4Y5Y6Y7Y8Y9Y10Y11Y12Y13Y14Y15
00000000000000000001
00010000000000000010
00100000000000000100
00110000000000001000
01000000000000010000
01010000000000100000
01100000000001000000
01110000000010000000
10000000000100000000
10010000001000000000
10100000010000000000
10110000100000000000
11000001000000000000
11010010000000000000
11100100000000000000
11111000000000000000

Circuit Diagram of 4 to 16 Decoder

4 to 16 Decoder Circuit
4 to 16 Decoder Circuit

Applications of Decoders

  • In every wireless communication, data security is the main concern. The decoders are mainly designed to provide security for data communication by designing standard encryption and decryption algorithms.
  • Decoders are used in audio systems to convert analogue audio into digital data.
  • Used as a decompressor to convert compressed data like images and videos into decompressed form.
  • Decoders use electronic circuits which convert computer instructions into CPU control signals.

Therefore, this is all about the 4 to 16 decoder circuit design using a 3 to 8 decoder circuit. Furthermore, any queries regarding this article or electronics projects you can comment us in the comment section below. here is a question for you, what is the use of Enable pin encoder/ decoder?

3 Comments

    1. Tarun Agarwal says:

      Hi Datta
      Here ‘E’ is nothing but enable pin. This enables the pin when negated, and makes the circuit inactive

  1. Fitflop Slippers says:

    WONDERFUL Post.thanks for share..extra wait .. ?

Add Comment