ZHCSOM7H July   2001  – September 2024 PCF8574A

PRODUCTION DATA  

  1.   1
  2. 1 特性
  3. 2 应用
  4. 3 说明
  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
    5. 5.5 Electrical Characteristics
    6. 5.6 I2C Interface Timing Requirements
    7. 5.7 Switching Characteristics
    8. 5.8 Typical Characteristics
  7. 6 Parameter Measurement Information
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
      1. 7.2.1 Simplified Block Diagram of Device
      2. 7.2.2 Simplified Schematic Diagram of Each P-Port Input/Output
    3. 7.3 Feature Description
      1. 7.3.1 I2C Interface
      2. 7.3.2 Interface Definition
      3. 7.3.3 Address Reference
    4. 7.4 Device Functional Modes
  9. 8 Application Information Disclaimer
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
        1. 8.2.1.1 Minimizing ICC When I/Os Control LEDs
      2. 8.2.2 Detailed Design Procedure
      3. 8.2.3 Application Curves
    3. 8.3 Power Supply Recommendations
      1. 8.3.1 Power-On Reset Requirements
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Documentation Support
      1. 9.1.1 Glossary
    2. 9.2 Receiving Notification of Documentation Updates
    3. 9.3 支持资源
    4. 9.4 Trademarks
    5. 9.5 静电放电警告
    6. 9.6 术语表
  11. 10Revision History
  12. 11Mechanical, 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)
  • DGV|20
  • DW|16
  • N|16
  • PW|20
  • RGY|20
散热焊盘机械数据 (封装 | 引脚)
订购信息

8.2.1.1 Minimizing ICC When I/Os Control LEDs

When the I/Os are used to control LEDs, normally they are connected to VCC through a resistor as shown in Figure 8-10. For a P-port configured as an input, ICC increases as VI becomes lower than VCC. The LED is a diode, with threshold voltage VT, and when a P-port is configured as an input the LED will be off but VI is a VT drop below VCC.

For battery-powered applications, it is essential that the voltage of P-ports controlling LEDs is greater than or equal to VCC when the P-ports are configured as input to minimize current consumption. Figure 8-2 shows a high-value resistor in parallel with the LED. Figure 8-3 shows VCC less than the LED supply voltage by at least VT. Both of these methods maintain the I/O VI at or above VCC and prevents additional supply current consumption when the P-port is configured as an input and the LED is off.

PCF8574A High-Value Resistor in Parallel With LEDFigure 8-2 High-Value Resistor in Parallel With LED
PCF8574A Device Supplied by a Lower VoltageFigure 8-3 Device Supplied by a Lower Voltage