ZHCSSH5 august   2023 LOG200

ADVANCE INFORMATION  

  1.   1
  2. 1 特性
  3. 2 应用
  4. 3 说明
  5. 4 Revision History
  6. 5 Pin Configuration and Functions
  7. 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 Typical Characteristics
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 High Speed, Logarithmic Current-to-Voltage Conversion
      2. 7.3.2 Voltage and Current References
      3. 7.3.3 Adaptive Photodiode Bias
      4. 7.3.4 Auxiliary Operational Amplifier
    4. 7.4 Device Functional Modes
  9. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Logarithmic Transfer Function
        1. 8.1.1.1 Logarithmic Conformity Error
    2. 8.2 Typical Application
      1. 8.2.1 Optical Current Sensing
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
        3. 8.2.1.3 Application Curves
    3. 8.3 Power Supply Recommendations
    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 Device Support
      1. 9.1.1 第三方产品免责声明
    2. 9.2 Documentation Support
      1. 9.2.1 Related Documentation
    3. 9.3 接收文档更新通知
    4. 9.4 支持资源
    5. 9.5 Trademarks
    6. 9.6 静电放电警告
    7. 9.7 术语表
  11. 10Mechanical, Packaging, and Orderable Information

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机械数据 (封装 | 引脚)
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订购信息

8.2.1.2 Detailed Design Procedure

The G8195-12 photodiode was used with a fixed reverse bias voltage of 5 V. The cathode was connected to the VS+ 5-V supply, and the anode to the I1 pin. GND is used for the VCM potential. The IBIAS feature and REF165 voltage reference were not needed; therefore, the IBIAS and REF165 pins are left floating. The auxiliary amplifier was not needed; therefore, the auxiliary amplifier was placed in a buffer configuration and used to buffer the REF25 reference voltage.

GND was used for the REFA input of the logarithmic difference amplifier. The circuit output follows the expression

Equation 8. V L O G O U T = 250 mV × log 10 I 1 1 µA

such that the expected output for a 100-nA input is –500 mV, the expected output for a 10-µA input is 250 mV, and so on.