ZHCSGW0E October   2017  – February 2020 OPA202 , OPA2202 , OPA4202

PRODUCTION DATA.  

  1. 1 特性
  2. 2 应用
  3. 3 说明
    1.     OPAx202 即使在直接驱动高容性负载时也表现优异
  4. 4 修订历史记录
  5. 5 Pin Configuration and Functions
    1.     Pin Functions: OPA202
    2.     Pin Functions: OPA2202
    3.     Pin Functions: OPA4202
  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: OPA202
    5. 6.5 Thermal Information: OPA2202
    6. 6.6 Thermal Information: OPA4202
    7. 6.7 Electrical Characteristics
    8. 6.8 Typical Characteristics
    9. 6.9 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Capacitive Load and Stability
      2. 7.3.2 Output Current Limit
      3. 7.3.3 Noise Performance
      4. 7.3.4 Phase-Reversal Protection
      5. 7.3.5 Thermal Protection
      6. 7.3.6 Electrical Overstress
      7. 7.3.7 EMI Rejection
      8. 7.3.8 EMIRR +IN Test Configuration
    4. 7.4 Device Functional Modes
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Basic Noise Calculations
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
      3. 8.2.3 Application Curve
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11器件和文档支持
    1. 11.1 器件支持
      1. 11.1.1 开发支持
        1. 11.1.1.1 TINA-TI（免费软件下载）
        2. 11.1.1.2 WEBENCH 滤波器设计器工具
        3. 11.1.1.3 TI 高精度设计
    2. 11.2 文档支持
      1. 11.2.1 相关文档
    3. 11.3 相关链接
    4. 11.4 接收文档更新通知
    5. 11.5 支持资源
    6. 11.6 商标
    7. 11.7 静电放电警告
    8. 11.8 Glossary
  12. 12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

8.1.1 Basic Noise Calculations

Low-noise circuit design requires careful analysis of all noise sources. External noise sources dominates in many cases; consider the effect of source resistance on overall op amp noise performance. Total noise of the circuit is the root-sum-square combination of all noise components.

The resistive portion of the source impedance produces thermal noise proportional to the square root of the resistance. Figure 42 shows this function. The source impedance is usually fixed; consequently, select the op amp and the feedback resistors to minimize the respective contributions to the total noise.

Figure 46 shows noninverting (A) and inverting (B) op amp circuit configurations with gain. In circuit configurations with gain, the feedback network resistors contribute noise. Typically, the current noise of the op amp reacts with the feedback resistors to create additional noise components. However, the extremely low current noise of the OPAx202 means that the current noise contribution is neglected.

The feedback resistor values are typically selected to make these noise sources negligible. Low impedance feedback resistors load the output of the amplifier. The equations for total noise are shown for both configurations.

OPA202 OPA2202 OPA4202 S008_SBOS427.gif
1. eN = the voltage noise of the amplifier = 9 nV/√Hz at 1 kHz.
2. iN = the current noise of the amplifier = 76 fA/√Hz at 1 kHz.
3. For additional resources on noise calculations, visit TI's Precision Labs.
Figure 46. Noise Calculation in Gain Configurations