Basic Information of 74LS138 3 to 8 Line Decoder IC

74LS138 3 to 8 Line Decoder IC utilizes the silicon-gate TTL technology. The design of the chip is for de-multiplexing or decoding applications. The 74LS138 comes with three inputs to eight output setup. It also has a special design that allows it to be used in data-routing applications or high-performance memory-decoding. It is effective in applications that require short propagation delay times.

The decoders have a special function of minimizing the effects of system decoding in high-performance memory systems.

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74LS138 3 to 8 Line Decoder IC Configuration

The basic configuration of the 74LS138 3 to 8 Line Decoder IC is that it has 3 inputs to 8 outputs setup. Each pin in the decoder has a special function that differentiates it from the rest.

A, B, C: these are address input pins

G2A (Enable input – active LOW), G2B (Enable input – active LOW), G1(Enable input – active HIGH)

GND – Ground

Y0, Y1, Y2, Y3, Y4, Y5, Y6, Y7: Out pins

Users can pick different available packages of this device.

Features of 74LS138 3 to 8 Line Decoder IC

The dominating features of the 74LS138 include the following:

  • It has been designed for high-speed performance
  • It simplifies cascading with the incorporation of the three enable pins
  • It has de-multiplexing capabilities
  • It delivers high performance
  • At has an ESD protection
  • It has balanced propagation delays
  • Its inputs can accept voltages that are higher than VCC
  • A typical propagation delay is 21nS
  • Another great feature is that it is consumption-friendly when it comes to power. It does not consume a lot of power, thus, help in reducing the cost of power. Its typical consumption is 32mW
  • It can operate within a wide range of temperatures i.e. from -40 degrees Celsius to +125 degrees Celsius.

An overview of 74LS138 3 to 8 Line Decoder IC

The chip has been designed for high-performance us in memory-decoding or data-routing applications that need short propagation delay times.

In most applications, any delays are not tolerated because the performance is determined by the memory unit data exchange rate. Using the 74LS138 3 line decoder is ideal in such applications because the delay times are permissible using this decoder.


You can use it for:

  • Servers
  • Line decoders
  • Digital systems
  • Line de-multiplexing
  • Memory circuits
  • Telecom circuits.