ZHCSIO3H January   2005  – February 2020 PCF8575

PRODUCTION DATA.  

  1. 1 特性
  2. 2 应用
  3. 3 说明
    1.     Device Images
      1.      简化原理图
  4. 4 修订历史记录
  5. 5 Pin Configuration and Functions
    1.     Pin Functions
  6. 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 I2C Interface Timing Requirements
    7. 6.7 Switching Characteristics
    8. 6.8 Typical Characteristics
  7. 7 Parameter Measurement Information
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
      1. 8.2.1 Logic Diagram (Positive Logic)
      2. 8.2.2 Simplified Schematic Diagram of Each P-Port Input/Output
    3. 8.3 Feature Description
      1. 8.3.1 I2C Interface
      2. 8.3.2 Interface Definition
      3. 8.3.3 Address Reference
    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 Minimizing ICC When I/Os Control LEDs
      2. 9.2.2 Detailed Design Procedure
      3. 9.2.3 Application Curves
  10. 10Power Supply Recommendations
    1. 10.1 Power-On Reset
    2. 10.2 System Impact
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12器件和文档支持
    1. 12.1 器件支持
    2. 12.2 文档支持
    3. 12.3 接收文档更新通知
    4. 12.4 支持资源
    5. 12.5 商标
    6. 12.6 静电放电警告
    7. 12.7 Glossary
  13. 13机械、封装和可订购信息

封装选项

机械数据 (封装 | 引脚)
散热焊盘机械数据 (封装 | 引脚)
订购信息

9.2.1.1 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 20. 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 21 shows a high-value resistor in parallel with the LED. Figure 22 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.

PCF8575 app_hival_r_cps126.gifFigure 21. High-Value Resistor in Parallel With LED
PCF8575 app_lowval_r_cps126.gifFigure 22. Device Supplied by a Lower Voltage