SCLS255N December   1995  – February 2024 SN54AHC74 , SN74AHC74

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1  Absolute Maximum Ratings
    2. 5.2  ESD Ratings
    3. 5.3  Recommended Operating Conditions
    4. 5.4  Thermal Information — SN74AHC74
    5. 5.5  Electrical Characteristics
    6. 5.6  Timing Requirements — VCC = 3.3 V ± 0.3 V
    7. 5.7  Timing Requirements — VCC = 5 V ± 0.5 V
    8. 5.8  Switching Characteristics — VCC = 3.3 V ± 0.5 V
    9. 5.9  Switching Characteristics — VCC = 5 V ± 0.5 V
    10. 5.10 Noise Characteristics
    11. 5.11 Operating Characteristics
  7. 6 Parameter Measurement Information
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Device Functional Modes
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
        1. 8.2.1.1 Input Considerations
        2. 8.2.1.2 Output Considerations
        3. 8.2.1.3 Power Considerations
      2. 8.2.2 Detailed Design Procedure
      3. 8.2.3 Application Curves
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
        1. 8.4.1.1 Layout Example
  10. 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
  11. 10Revision History
  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

8.1 Application Information

Toggle switches are typically large, mechanically complex, and relatively expensive. It is desirable to use a momentary switch instead because they are small, mechanically simple, and cost less. Some systems require the functionality of a toggle switch, but are space or cost constrained and must use a momentary switch instead. External Schmitt-trigger buffers are used to remove noisy inputs into the (CLK) and (D) inputs.

If the data input (D) of the SNx4AHC74 is tied to the inverted output (Q), then each clock pulse will cause the value at the output (Q) to toggle. The momentary switch can be debounced and directly connected to the clock input (CLK) to toggle the output.