SCLS266O December   1995  – July 2024 SN54AHCT138 , SN74AHCT138

PRODUCTION DATA  

  1.   1
  2. Features
  3. Description
  4. Pin Configuration and Functions
  5. Specifications
    1. 4.1 Absolute Maximum Ratings
    2. 4.2 ESD Ratings
    3. 4.3 Recommended Operating Conditions
    4. 4.4 Thermal Information
    5. 4.5 Electrical Characteristics
    6. 4.6 Switching Characteristics
    7. 4.7 Operating Characteristics
    8. 4.8 Typical Characteristics
  6. Parameter Measurement Information
  7. Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Device Functional Modes
  8. Application and Implementation
    1. 7.1 Application Information
    2. 7.2 Power Supply Recommendations
    3. 7.3 Layout
      1. 7.3.1 Layout Guidelines
  9. Device and Documentation Support
    1. 8.1 Documentation Support
      1. 8.1.1 Related Links
    2. 8.2 Receiving Notification of Documentation Updates
    3. 8.3 Support Resources
    4. 8.4 Trademarks
    5. 8.5 Electrostatic Discharge Caution
    6. 8.6 Glossary
  10. Revision History
  11. 10Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • W|16
  • J|16
  • FK|20
Thermal pad, mechanical data (Package|Pins)
Orderable Information

Overview

When employed with high-speed memories utilizing a fast enable circuit, the delay times of this decoder and the enable time of the memory usually are less than the typical access time of the memory. This means that the effective system delay introduced by the decoder is negligible.

The conditions at the binary-select inputs and the three enable inputs select one of eight output lines. 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, and a 32-line decoder requires only one inverter. An enable input can be used as a data input for demultiplexing applications.