ZHCSQY6D august   2022  – april 2023 OPA2992-Q1 , OPA4992-Q1 , OPA992-Q1

PRODMIX  

  1. 1 特性
  2. 2 应用
  3. 3 说明
  4. 4 Revision History
  5. 5 Pin Configuration and 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 for Single Channel
    5. 6.5 Thermal Information for Dual Channel
    6. 6.6 Thermal Information for Quad Channel
    7. 6.7 Electrical Characteristics
    8. 6.8 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 Input Protection Circuitry
      2. 7.3.2 EMI Rejection
      3. 7.3.3 Thermal Protection
      4. 7.3.4 Capacitive Load and Stability
      5. 7.3.5 Common-Mode Voltage Range
      6. 7.3.6 Phase Reversal Protection
      7. 7.3.7 Electrical Overstress
      8. 7.3.8 Overload Recovery
      9. 7.3.9 Typical Specifications and Distributions
    4. 7.4 Device Functional Modes
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 Low-Side Current Measurement
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
        3. 8.2.1.3 Application Curve
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Example
  9. 9 Device and Documentation Support
    1. 9.1 Device Support
      1. 9.1.1 Development Support
        1. 9.1.1.1 TINA-TI (Free Software Download)
    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
  10. 10Mechanical, 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

8.2.1.2 Detailed Design Procedure

The transfer function of the circuit in Figure 8-1 is given in Equation 1:

Equation 1. V O U T   =   I L O A D   ×   R S H U N T   ×   G a i n

The load current (ILOAD) produces a voltage drop across the shunt resistor (RSHUNT). The load current is set from 0 A to 1 A. To keep the shunt voltage below 100 mV at maximum load current, the largest shunt resistor is defined using Equation 2:

Equation 2. R S H U N T   =   V S H U N T _ M A X I L O A D _ M A X   =   100   m V 1   A   =   100   m Ω

Using Equation 2, RSHUNT is calculated to be 100 mΩ. The voltage drop produced by ILOAD and RSHUNT is amplified by the OPA992-Q1 to produce an output voltage of 0 V to 4.9 V. The gain needed by the OPA992-Q1 to produce the necessary output voltage is calculated using Equation 3:

Equation 3. G a i n   =   V O U T _ M A X     -   V O U T _ M I N V I N _ M A X   -   V I N _ M I N    

Using Equation 3, the required gain is calculated to be 49 V/V, which is set with resistors RF and RG. Equation 4 is used to size the resistors, RF and RG, to set the gain of the OPA992-Q1 to 49 V/V.

Equation 4. G a i n   =   1   +   R F R G  

Choosing RF as 5.76 kΩ, RG is calculated to be 120 Ω. RF and RG were chosen as 5.76 kΩ and 120 Ω because the values are standard value resistors that create a 49:1 ratio. Other resistors that create a 49:1 ratio can also be used. However, excessively large resistors generate thermal noise that exceeds the intrinsic noise of the op amp. Figure 8-2 shows the measured transfer function of the circuit shown in Figure 8-1.