The 74F138DC is a 3-to-8 line decoder/demultiplexer manufactured by Rochester Electronics. This device is part of the 74F family of advanced Schottky TTL logic, providing high-speed performance. The decoder accepts three binary address inputs (A0, A1, and A2) and, depending on the input, activates one of the eight output lines (Y0-Y7). Rochester Electronics specializes in supplying components that are no longer actively manufactured by the original producers, which ensures the continued availability of essential parts.

Applications:

• Memory address decoding.
• Data routing and selection.
• Chip selection in memory systems.
• Control signal generation.
• Peripheral device selection.

Features:

• 3-to-8 line decoding.
• High-speed operation.
• Three enable inputs for cascading.
• Low power consumption.
• Active-low outputs.

Benefits:

• Simplifies address decoding logic.
• Improves system performance through rapid signal processing.
• Allows for expansion to larger decoding networks.
• Reduces overall power consumption.
• Provides a direct interface to other logic devices with active-low inputs.

Additional Details:

The 74F138DC typically operates from a 5V power supply and comes in a ceramic dual-in-line package (CERDIP). Its key electrical characteristics include a propagation delay of approximately 4 ns and a supply current of roughly 30 mA. The device features three enable inputs (G1, /G2A, and /G2B), which allow for easy cascading of multiple decoders to create larger decoding arrays. The active-low outputs simplify the design of systems with active-low logic. Common applications include memory systems, where the decoder selects a specific memory chip based on the address, and control systems, where it enables specific functions based on the control inputs. Because this part is sourced through Rochester Electronics, it allows continued support for legacy systems that depend on the function of this device. The 74F138 from Rochester ensures the continued availability of this function for military, industrial, and other long lifecycle product needs.