SCAS982 March   2024 SN74AHCT257

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6.   6
  7.   7
  8. 5 Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 ESD Ratings
    3. 5.3 Recommended Operating Conditions
    4. 5.4 Thermal Information
    5. 5.5 Electrical Characteristics
    6. 5.6 Switching Characteristics
    7. 5.7 Noise Characteristics
    8. 5.8 Typical Characteristics
  9. 6 Parameter Measurement Information
  10. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Balanced CMOS 3-State Outputs
      2. 7.3.2 TTL-Compatible CMOS Inputs
      3. 7.3.3 Clamp Diode Structure
    4. 7.4 Device Functional Modes
  11. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
    3. 8.3 Design Requirements
      1. 8.3.1 Power Considerations
      2. 8.3.2 Input Considerations
      3. 8.3.3 Output Considerations
    4. 8.4 Detailed Design Procedure
    5. 8.5 Application Curve
    6. 8.6 Power Supply Recommendations
    7. 8.7 Layout
      1. 8.7.1 Layout Guidelines
      2. 8.7.2 Layout Example
  12. 9 Device and Documentation Support
    1. 9.1 Documentation Support
      1. 9.1.1 Related Documentation
    2. 9.2 Receiving Notification of Documentation Updates
    3. 9.3 Support Resources
    4. 9.4 Trademarks
    5. 9.5 Electrostatic Discharge Caution
    6. 9.6 Glossary
  13. 10Revision History
  14. 11Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • BQB|16
  • PW|16
Thermal pad, mechanical data (Package|Pins)
Orderable Information

8.7.1 Layout Guidelines

When using multiple-input and multiple-channel logic devices, inputs must never be left floating. In many cases, functions or parts of functions of digital logic devices are unused; for example, when only two inputs of a triple-input AND gate are used or only 3 of the 4 buffer gates are used. Such unused input pins must not be left unconnected because the undefined voltages at the outside connections result in undefined operational states. All unused inputs of digital logic devices must be connected to a logic high or logic low voltage, as defined by the input voltage specifications, to prevent them from floating. The logic level that must be applied to any particular unused input depends on the function of the device. Generally, the inputs are tied to GND or VCC, whichever makes more sense for the logic function or is more convenient.