JAJS198L October   2006  – January 2020 OPA211


  1. 特長
  2. アプリケーション
  3. 概要
    1.     Device Images
      1.      入力電圧ノイズ密度と周波数との関係
  4. 改訂履歴
  5. 概要(続き)
  6. Pin Configuration and Functions
    1.     Pin Functions: OPA211
    2.     Pin Functions: OPA2211
  7. Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information: OPA211 and OPA211A
    5. 7.5 Thermal Information: OPA2211 and OPA2211A
    6. 7.6 Electrical Characteristics: Standard Grade OPAx211A
    7. 7.7 Electrical Characteristics: High-Grade OPAx211
    8. 7.8 Typical Characteristics
  8. Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Total Harmonic Distortion Measurements
    4. 8.4 Device Functional Modes
      1. 8.4.1 Shutdown
  9. Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 Operating Voltage
      2. 9.1.2 Input Protection
      3. 9.1.3 Noise Performance
      4. 9.1.4 Basic Noise Calculations
      5. 9.1.5 EMI Rejection
      6. 9.1.6 EMIRR +IN Test Configuration
      7. 9.1.7 Electrical Overstress
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
      3. 9.2.3 Application Curve
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
      1. 11.1.1 SON Layout Guidelines
    2. 11.2 Layout Example
  12. 12デバイスおよびドキュメントのサポート
    1. 12.1 デバイス・サポート
      1. 12.1.1 開発サポート
        1. TINA-TI™ (無料のダウンロード・ソフトウェア)
        2. TI Precision Designs
        3. WEBENCH® Filter Designer
    2. 12.2 ドキュメントのサポート
      1. 12.2.1 関連資料
    3. 12.3 関連リンク
    4. 12.4 ドキュメントの更新通知を受け取る方法
    5. 12.5 サポート・リソース
    6. 12.6 商標
    7. 12.7 静電気放電に関する注意事項
    8. 12.8 Glossary
  13. 13メカニカル、パッケージ、および注文情報



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 operational amplifiers is a change in the offset voltage as a result of RF signal rectification. An operational amplifier 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 operational amplifier. In general, only the noninverting input is tested for EMIRR for the following three reasons:

  1. Operational amplifier input pins are known to be the most sensitive to EMI, and typically rectify RF signals better than the supply or output pins.
  2. The noninverting and inverting operational amplifier inputs have symmetrical physical layouts and exhibit nearly matching EMIRR performance.
  3. EMIRR is easier to measure on noninverting pins than on other pins because the noninverting input terminal can be isolated on a printed-circuit-board (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 46

The EMIRR IN+ of the OPA211 is plotted versus frequency as shown in Figure 46. If available, any dual and quad operational amplifier device versions have nearly similar EMIRR IN+ performance. The OPA211 unity-gain bandwidth is 45 MHz. EMIRR performance below this frequency denotes interfering signals that fall within the operational amplifier bandwidth.

Detailed information can also be found in the EMI Rejection Ratio of Operational Amplifiers application report, available for download from www.ti.com.

OPA211 OPA2211 D051_SBOS377.gifFigure 46. OPA211 EMIRR

Table 1 shows the EMIRR IN+ values for the OPA211 at particular frequencies commonly encountered in real-world applications. Applications listed in Table 1 may be centered on or operated near the particular frequency shown. This information may 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 1. OPA211 EMIRR IN+ for Frequencies of Interest

400 MHz Mobile radio, mobile satellite, space operation, weather, radar, ultra-high frequency (UHF) applications 48.4 dB
900 MHz Global system for mobile communications (GSM) applications, radio communication, navigation, GPS (to 1.6 GHz), GSM, aeronautical mobile, UHF applications 34.6 dB
1.8 GHz GSM applications, mobile personal communications, broadband, satellite, L-band (1 GHz to 2 GHz) 46 dB
2.4 GHz 802.11b, 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) 56.9 dB
3.6 GHz Radiolocation, aero communication and navigation, satellite, mobile, S-band 61.5 dB
5 GHz 802.11a, 802.11n, aero communication and navigation, mobile communication, space and satellite operation, C-band (4 GHz to 8 GHz) 76.7 dB