ZHCSP28B July   2021  – October 2022 SN74HCS244


  1. 特性
  2. 应用
  3. 说明
  4. Revision History
  5. Pin Configuration and Functions
  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 Switching Characteristics
    7. 6.7 Operating Characteristics
    8. 6.8 Typical Characteristics
  7. Parameter Measurement Information
  8. Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Balanced CMOS 3-State Outputs
      2. 8.3.2 Balanced CMOS Push-Pull Outputs
      3. 8.3.3 Open-Drain CMOS Outputs
      4. 8.3.4 CMOS Schmitt-Trigger Inputs
      5. 8.3.5 TTL 兼容型 CMOS 输入
      6. 8.3.6 Standard CMOS Inputs
      7. 8.3.7 Clamp Diode Structure
      8. 8.3.8 Wettable Flanks
    4. 8.4 Device Functional Modes
  9. Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
        1. Power Considerations
        2. Input Considerations
        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 接收文档更新通知
    3. 12.3 支持资源
    4. 12.4 Trademarks
    5. 12.5 Electrostatic Discharge Caution
    6. 12.6 术语表
  13. 13Mechanical, Packaging, and Orderable Information


机械数据 (封装 | 引脚)
散热焊盘机械数据 (封装 | 引脚)

Balanced CMOS 3-State Outputs

This device includes balanced CMOS 3-state outputs. Driving high, driving low, and high impedance are the three states that these outputs can be in. The term balanced indicates that the device can sink and source similar currents. The drive capability of this device may create fast edges into light loads, so routing and load conditions should be considered to prevent ringing. Additionally, the outputs of this device are capable of driving larger currents than the device can sustain without being damaged. It is important for the output power of the device to be limited to avoid damage due to overcurrent. The electrical and thermal limits defined in the Absolute Maximum Ratings must be followed at all times.

When placed into the high-impedance mode, the output will neither source nor sink current, with the exception of minor leakage current as defined in the Electrical Characteristics table. In the high-impedance state, the output voltage is not controlled by the device and is dependent on external factors. If no other drivers are connected to the node, then this is known as a floating node and the voltage is unknown. A pull-up or pull-down resistor can be connected to the output to provide a known voltage at the output while it is in the high-impedance state. The value of the resistor will depend on multiple factors, including parasitic capacitance and power consumption limitations. Typically, a 10-kΩ resistor can be used to meet these requirements.

Unused 3-state CMOS outputs should be left disconnected.