The TC74ACT138FT is a 3-to-8 line decoder/demultiplexer from Toshiba Semiconductor and Storage. This device accepts three binary weighted inputs (A0, A1, A2) and, depending on the state of three enable inputs (E1, E2, E3), provides eight mutually exclusive active-LOW outputs (Y0 to Y7). The device can be used as a decoder to convert a 3-bit binary address to one of eight output lines, or as a demultiplexer to route data from one input to one of eight outputs.

Applications

• Memory address decoding
• Data routing
• Logic function generation
• Chip select decoding
• Instrumentation

Features

• High-speed operation: tpd = 7.5 ns (typ.) at VCC = 5V
• Low power dissipation: ICC = 4 µA (max) at VCC = 5V
• Operating voltage range: VCC = 4.5V to 5.5V
• TTL compatible inputs
• Enable inputs for easy expansion
• ESD protection exceeds 2000V HBM
• Available in a small surface mount package (SOIC)

Benefits

• Improved system performance due to high-speed operation.
• Reduced power consumption leading to longer battery life in portable devices.
• Easy interfacing with other TTL logic.
• Simplified expansion using the enable inputs.
• Increased reliability due to ESD protection.
• Space-saving design with the small surface mount package.

The TC74ACT138FT features three enable inputs: E1 (active HIGH), E2 (active LOW), and E3 (active LOW). The device is enabled when E1 is HIGH, and both E2 and E3 are LOW. If any of these conditions are not met, all eight outputs are forced HIGH. This multiple enable function allows easy parallel expansion of the device to achieve larger decoding configurations.

The device is supplied in a 16-pin SOIC (Small Outline Integrated Circuit) package suitable for surface mount technology. The operating temperature range is typically -40°C to +85°C, making it suitable for industrial applications.