74138 IC

The 74138 IC is a 3-to-8 line decoder and demultiplexer from the 74xx TTL logic family. It takes 3 binary select inputs and activates one of eight outputs based on the input combination. All outputs are active LOW, making it ideal for memory decoding, device selection, and digital control circuits.

Key Features

• 3-to-8 line decoder / demultiplexer

• Active LOW outputs

• Three enable inputs (2 active LOW, 1 active HIGH)

• High-speed TTL logic operation

• Output fan-out suitable for direct TTL loads

• Standard 16-pin DIP package

• Reliable and widely used logic IC

Pin Configuration

• Inputs: A, B, C (Select lines)

• Enable Pins: G1 (Active HIGH), G2A & G2B (Active LOW)

• Outputs: Y0 to Y7 (Active LOW)

• Supply Voltage: 5V DC (Typical TTL)

Applications

• Memory address decoding

• Microprocessor & microcontroller interfacing

• Device and chip selection circuits

• Data routing and signal distribution

• Digital logic experiments & education kits

• Industrial control systems