The HD74HC138RP is a high-speed silicon-gate CMOS 3-to-8 line decoder/demultiplexer manufactured by Hitachi. This device accepts three binary weighted inputs (A0, A1, A2) and, depending upon the condition of the three Enable inputs (E1, E2, and E3), provides eight mutually exclusive active-low outputs (O0 through O7). The HD74HC138RP features high noise immunity and low power consumption, making it suitable for a variety of decoding and demultiplexing applications.

Applications

• Memory Decoding: Used to select one of several memory banks in a memory system.
• Address Decoding: Decodes address lines to select specific peripherals or memory locations.
• Data Routing: Demultiplexes data from a single input to one of eight outputs.
• Chip Select Logic: Generates chip select signals for enabling or disabling various integrated circuits.
• Industrial Control: Used in industrial control systems for decoding control signals and activating specific functions.

Features

• 3-to-8 Line Decoder/Demultiplexer: Decodes a 3-bit binary input into one of eight active-low outputs.
• High-Speed CMOS: Offers high-speed operation with low power consumption.
• Enable Inputs: Three enable inputs (E1, E2, E3) control the operation of the decoder. E1 and E2 are active-low, and E3 is active-high.
• Active-Low Outputs: Outputs are normally high and go low when selected.
• Fanout Capability: High fanout capability allows it to drive multiple loads.
• Wide Operating Voltage Range: Operates over a wide voltage range, typically 2V to 6V.
• RP Package: Shipped in a plastic dual-in-line package (DIP).

Benefits

• Versatile Decoding Function: Provides a versatile and widely used decoding function for various applications.
• High Performance: Offers high speed and low power consumption, making it suitable for demanding applications.
• Easy to Use: Simple and straightforward to implement in decoding circuits.
• Reduces Component Count: Integrates decoding logic into a single package, reducing the overall component count.
• Improved System Performance: Enhances system performance through fast and efficient decoding.

Additional Details

The HD74HC138RP operates according to the following truth table: When E1 or E2 are high, or E3 is low, all outputs are high. When E1 and E2 are low, and E3 is high, the output corresponding to the binary value of A0, A1, and A2 will be low, while all other outputs remain high. The device utilizes silicon-gate CMOS technology for low power consumption and high noise immunity. It is important to observe the maximum ratings for voltage and current to prevent damage. The device is RoHS compliant, indicating it meets environmental regulations for hazardous substances. Input and output characteristics are well-defined, enabling reliable circuit design.