SN54AHC138 and SN74AHC138 are 3-line to 8-line decoders/demultiplexers designed for high-speed memory decoders and data transmission systems. They incorporate three enable inputs to simplify cascading and/or data reception. These products have high output current and low power consumption.
This document provides technical specifications and application information for the SN54AHC138 and SN74AHC138 3-line to 8-line decoder/demultiplexer devices. Designed for high-performance memory-decoding and data-routing applications, these chips utilize very short propagation-delay times to minimize system decoding effects in high-speed memory systems.
The datasheet details absolute maximum ratings, recommended operating conditions, electrical characteristics, and switching characteristics over various temperature ranges. It includes logic diagrams, pin configurations for multiple packages (such as PDIP, SOIC, SSOP, TSSOP), and application examples demonstrating how to implement 24-line and 32-line decoding schemes using cascading.
| High-Level Output Current (VCC=3.3V) | -4 mA |
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Two active-low and one active-high enable inputs reduce the need for external gates or inverters when expanding.
A 24-line decoder can be implemented without external inverters using these devices.
The power dissipation capacitance (Cp) is typically 13 pF when unloaded at f=1MHz.