The 74LCX138 is a high-performance, low-voltage 3-to-8 line decoder/demultiplexer from Fairchild Semiconductor (now ON Semiconductor). It accepts three address inputs (A0-A2) and enables one of eight outputs (Y0-Y7) based on the binary value of the input address. The device also features three enable inputs (E1, E2, E3), which must be at their active levels for the device to be enabled.

Applications

• Memory addressing and decoding
• Data routing and multiplexing
• Chip selection
• Address decoding in microprocessor-based systems
• Logic level translation

Features

• Low voltage operation: 2.0V to 5.5V
• High-speed operation: tpd = 4.5 ns (typical at 3.3V)
• Low power consumption: ICC = 4 μA (maximum)
• 3-to-8 line decoding
• Three enable inputs for easy expansion
• Outputs are active LOW
• Available in various packages including SOIC, TSSOP, and DIP

Benefits

• Fast switching speed for high-performance applications
• Low power consumption for battery-powered devices
• Simple and efficient address decoding
• Versatile for various digital logic applications
• Reduces component count and board space
• Easy to interface with other logic devices

Additional Details

The 74LCX138 is designed for applications requiring high speed and low power consumption. The low voltage operation allows it to be used in modern portable and embedded systems. The three enable inputs provide flexibility in cascading multiple decoders for larger address spaces. When the device is enabled, one of the eight outputs is driven low, while the other outputs remain high. The 74LCX138 is a popular choice for a wide range of digital logic applications due to its speed, low power, and ease of use.

Specifically, the enable inputs (E1, E2, E3) work as follows: E1 and E2 are active LOW, and E3 is active HIGH. Therefore, the decoder is enabled only when E1 and E2 are LOW, and E3 is HIGH. If any of these conditions are not met, all outputs (Y0-Y7) will be HIGH, regardless of the address inputs.

The device's high-speed operation is achieved through advanced CMOS technology, minimizing propagation delays and ensuring reliable performance in demanding applications. Available in multiple packages, the 74LCX138 can be easily integrated into various PCB designs.