SCLS087F December   1982  – June 2021 SN54HC21 , SN74HC21

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 Recommended Operating Conditions
    3. 6.3 Thermal Information
    4. 6.4 Electrical Characteristics - 74
    5. 6.5 Electrical Characteristics - 54
    6. 6.6 Switching Characteristics - 74
    7. 6.7 Switching Characteristics - 54
    8. 6.8 Operating Characteristics
    9. 6.9 Typical Characteristics
  7. 7 Parameter Measurement Information
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Balanced CMOS Push-Pull Outputs
      2. 8.3.2 Standard CMOS Inputs
      3. 8.3.3 Clamp Diode Structure
    4. 8.4 Device Functional Modes
  9. 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 Power Considerations
        2. 9.2.1.2 Input Considerations
        3. 9.2.1.3 Output Considerations
      2. 9.2.2 Detailed Design Procedure
      3. 9.2.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Documentation Support
      1. 12.1.1 Related Documentation
    2. 12.2 Support Resources
    3. 12.3 Trademarks
    4. 12.4 Electrostatic Discharge Caution
    5. 12.5 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

封装选项

请参考 PDF 数据表获取器件具体的封装图。

机械数据 (封装 | 引脚)
  • D|14
  • PW|14
  • N|14
  • NS|14
散热焊盘机械数据 (封装 | 引脚)
订购信息

9.2.1.1 Power Considerations

Ensure the desired supply voltage is within the range specified in the Section 6.2. The supply voltage sets the device's electrical characteristics as described in the Section 6.4.

The supply must be capable of sourcing current equal to the total current to be sourced by all outputs of the SN74HC21 plus the maximum supply current, ICC, listed in the Section 6.4. The logic device can only source or sink as much current as it is provided at the supply and ground pins, respectively. Be sure not to exceed the maximum total current through GND or VCC listed in the Section 6.1.

Total power consumption can be calculated using the information provided in CMOS Power Consumption and Cpd Calculation.

Thermal increase can be calculated using the information provided in Thermal Characteristics of Standard Linear and Logic (SLL) Packages and Devices.

CAUTION:

The maximum junction temperature, TJ(max) listed in the Section 6.1, is an additional limitation to prevent damage to the device. Do not violate any values listed in the Section 6.1. These limits are provided to prevent damage to the device.