ZHCSJA0F June   2010  – March 2023 OPA140 , OPA2140 , OPA4140

PRODUCTION DATA  

  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: OPA140
    5. 6.5 Thermal Information: OPA2140
    6. 6.6 Thermal Information: OPA4140
    7. 6.7 Electrical Characteristics
    8. 6.8 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  Operating Voltage
      2. 7.3.2  Capacitive Load and Stability
      3. 7.3.3  Output Current Limit
      4. 7.3.4  Noise Performance
      5. 7.3.5  Basic Noise Calculations
      6. 7.3.6  Phase-Reversal Protection
      7. 7.3.7  Thermal Protection
      8. 7.3.8  Electrical Overstress
      9. 7.3.9  EMI Rejection
      10. 7.3.10 EMIRR +IN Test Configuration
    4. 7.4 Device Functional Modes
  9. 8 Application and Implementation
    1. 8.1 Application Information
    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 滤波器设计工具
        4. 9.1.1.4 TI 参考设计
    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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7.3.9 EMI Rejection

The electromagnetic interference (EMI) rejection ratio, or EMIRR, describes the EMI immunity of operational amplifiers. An adverse effect that is common to many op amps is a change in the offset voltage as a result of RF signal rectification. An op amp that is more efficient at rejecting this change in offset as a result of EMI has a higher EMIRR and is quantified by a decibel value. Measuring EMIRR can be performed in many ways, but this section provides the EMIRR IN+, which specifically describes the EMIRR performance when the RF signal is applied to the noninverting input pin of the op amp. In general, only the noninverting input is tested for EMIRR for the following three reasons:

  • Op amp input pins are known to be the most sensitive to EMI, and typically rectify RF signals better than the supply or output pins.
  • The noninverting and inverting op amp inputs have symmetrical physical layouts and exhibit nearly matching EMIRR performance
  • EMIRR is easier to measure on noninverting pins than on other pins because the noninverting input terminal can be isolated on a PCB. This isolation allows the RF signal to be applied directly to the noninverting input terminal with no complex interactions from other components or connecting PCB traces. Figure 7-6

GUID-AA56271E-7799-4072-A649-A19A1482DBE5-low.gifFigure 7-6 OPA2140 EMIRR

The EMIRR IN+ of the OPA2140 is plotted versus frequency as shown in .If available, any dual and quad op amp device versions have nearly similar EMIRR IN+ performance. The OPA2140 unity-gain bandwidth is
11 MHz. EMIRR performance below this frequency denotes interfering signals that fall within the op amp bandwidth.

For more information, see the EMI Rejection Ratio of Operational Amplifiers Application Report, available for download from www.ti.com.

Table 7-1 lists the EMIRR IN+ values for the OPA2140 at particular frequencies commonly encountered in real-world applications. Applications listed in Table 7-1 can be centered on or operated near the particular frequency shown. This information can be of special interest to designers working with these types of applications, or working in other fields likely to encounter RF interference from broad sources, such as the industrial, scientific, and medical (ISM) radio band.

Table 7-1 OPA2140 EMIRR IN+ for Frequencies of Interest
FREQUENCYAPPLICATION OR ALLOCATIONEMIRR IN+
400 MHzMobile radio, mobile satellite, space operation, weather, radar, ultra-high frequency (UHF) applications53.1 dB
900 MHzGlobal system for mobile communications (GSM) applications, radio communication, navigation, GPS (to 1.6 GHz), GSM, aeronautical mobile, UHF applications72.2 dB
1.8 GHzGSM applications, mobile personal communications, broadband, satellite, L-band (1 GHz to 2 GHz)80.7 dB
2.4 GHz802.11b, 802.11g, 802.11n, Bluetooth®, mobile personal communications, industrial, scientific and medical (ISM) radio band, amateur radio and satellite, S-band (2 GHz to 4 GHz)86.8 dB
3.6 GHzRadiolocation, aero communication and navigation, satellite, mobile, S-band91.7 dB
5 GHz802.11a, 802.11n, aero communication and navigation, mobile communication, space and satellite operation, C-band (4 GHz to 8 GHz)96.6 dB