ZHCSLZ5D October   2020  – December 2023 OPA3S328

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 Timing Diagram
    7. 5.7 Typical Characteristics
  7. 6 Parameter Measurement Information
    1. 6.1 Switch Characterization Configurations
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Low Operating Voltage
      2. 7.3.2 Input and ESD Protection
      3. 7.3.3 Programmable Switches
      4. 7.3.4 Rail-to-Rail Input
      5. 7.3.5 Phase Reversal
    4. 7.4 Device Functional Modes
      1. 7.4.1 Power-Down Mode
  9. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Capacitive Load and Stability
      2. 8.1.2 EMI Susceptibility and Input Filtering
      3. 8.1.3 Transimpedance Amplifier
        1. 8.1.3.1 Optimizing the Transimpedance Circuit
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
      3. 8.2.3 Application Curve
    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 Development Support
        1. 9.1.1.1 PSpice® for TI
        2. 9.1.1.2 TINA-TI™ 仿真软件（免费下载）
        3. 9.1.1.3 TI 参考设计
        4. 9.1.1.4 滤波器设计工具
    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. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information

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

8.1.3 Transimpedance Amplifier

Wide gain bandwidth, low-input bias current, low input voltage, and current noise make the OPA3S328 an excellent wideband photodiode transimpedance amplifier. Low-voltage noise is important because photodiode capacitance causes the effective noise gain of the circuit to increase at high frequency.

Figure 8-3 shows the key elements to a transimpedance design, which are:

  • expected diode capacitance (CD); include the parasitic input common-mode voltage and differential-mode input capacitance
  • desired transimpedance gain (RF)
  • gain-bandwidth (GBW) for the OPA3S328 (40 MHz)

With these three variables set, the feedback capacitor value (CF) can be set to control the frequency response. CF includes the stray capacitance of RF, which is 0.2 pF for a typical surface-mount resistor.

GUID-20201001-CA0I-JQLS-RQ1F-XFKBCCXVSTPP-low.gif
NOTE: CF is optional to prevent gain peaking, and includes the stray capacitance of RF.
Figure 8-3 Dual-Supply Transimpedance Amplifier

For optimized frequency response, set the feedback pole as follows:

Equation 1. GUID-40D52EF3-63CB-49DC-89D7-CF6941CCA5F4-low.gif

Equation 2 calculates the bandwidth.

Equation 2. GUID-B413E593-9715-494C-B195-93CD235D1AEB-low.gif

For single-supply applications, the +IN input can be biased with a positive dc voltage to allow the output to reach true zero when the photodiode is not exposed to any light, and respond without the added delay that results from coming out of the negative rail. Figure 8-4 shows this configuration. This bias voltage also appears across the photodiode, providing a reverse bias for faster operation.

GUID-20201002-CA0I-8Q5B-WKQK-GWTQRX6NFVVW-low.gif
NOTE: CF is optional to prevent gain peaking, and includes the stray capacitance of RF.
Figure 8-4 Single-Supply Transimpedance Amplifier

For more information, see the Compensate Transimpedance Amplifiers Intuitively and Build a Programmable Gain Transimpedance Amplifier Using the OPA3S328 application reports.