SCLS263R December   1995  – October 2023 SN54AHCT74 , SN74AHCT74

PRODMIX  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Revision History
  6. 5 Pin Configuration and Functions
  7. 6 Specifications
    1. 6.1  Absolute Maximum Ratings
    2. 6.2  ESD Ratings
    3. 6.3  Recommended Operating Conditions
    4. 6.4  Thermal Information
    5. 6.5  Electrical Characteristics
    6. 6.6  Timing Requirements
    7. 6.7  Switching Characteristics
    8. 6.8  Noise Characteristics
    9. 6.9  Operating Characteristics
    10. 6.10 Typical Characteristics
  8. 7 Parameter Measurement Information
  9. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 TTL-Compatible CMOS Inputs
      2. 8.3.2 Balanced CMOS Push-Pull Outputs
      3. 8.3.3 Clamp Diode Structure
    4. 8.4 Device Functional Modes
  10. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
        1. 9.2.1.1 Input Considerations
        2. 9.2.1.2 Output Considerations
        3. 9.2.1.3 Power Considerations
      2. 9.2.2 Detailed Design Procedure
      3. 9.2.3 Application Curves
    3. 9.3 Power Supply Recommendations
    4. 9.4 Layout
      1. 9.4.1 Layout Guidelines
        1. 9.4.1.1 Layout Example
  11. 10Device and Documentation Support
    1. 10.1 Receiving Notification of Documentation Updates
    2. 10.2 Support Resources
    3. 10.3 Trademarks
    4. 10.4 Electrostatic Discharge Caution
    5. 10.5 Glossary
  12. 11Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • J|14
  • FK|20
  • W|14
Thermal pad, mechanical data (Package|Pins)
Orderable Information

8.3.1 TTL-Compatible CMOS Inputs

This device includes TTL-compatible CMOS inputs. These inputs are specifically designed to interface with TTL logic devices by having a reduced input voltage threshold.

TTL-compatible CMOS inputs are high impedance and are typically modeled as a resistor in parallel with the input capacitance given in the Electrical Characteristics. The worst case resistance is calculated with the maximum input voltage, given in the Absolute Maximum Ratings, and the maximum input leakage current, given in the Electrical Characteristics, using Ohm's law (R = V ÷ I).

TTL-compatible CMOS inputs require that input signals transition between valid logic states quickly, as defined by the input transition time or rate in the Recommended Operating Conditions table. Failing to meet this specification will result in excessive power consumption and could cause oscillations. More details can be found in the Implications of Slow or Floating CMOS Inputs application report.

Do not leave TTL-compatible CMOS inputs floating at any time during operation. Unused inputs must be terminated at VCC or GND. If a system will not be actively driving an input at all times, a pull-up or pull-down resistor can be added to provide a valid input voltage during these times. The resistor value will depend on multiple factors; however, a 10-kΩ resistor is recommended and will typically meet all requirements.