JAJSGT8F June   2010  – March 2023 OPA140 , OPA2140 , OPA4140

PRODUCTION DATA  

  1.   1
  2. 1 特長
  3. 2 アプリケーション
  4. 3 概要
  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™シミュレーション・ソフトウェア (無償ダウンロード)
        3. 9.1.1.3 フィルタ設計ツール
        4. 9.1.1.4 TI のリファレンス・デザイン
    2. 9.2 Documentation Support
      1. 9.2.1 Related Documentation
    3. 9.3 ドキュメントの更新通知を受け取る方法
    4. 9.4 サポート・リソース
    5. 9.5 Trademarks
    6. 9.6 静電気放電に関する注意事項
    7. 9.7 用語集
  11. 10Mechanical, Packaging, and Orderable Information

パッケージ・オプション

メカニカル・データ（パッケージ｜ピン）
サーマルパッド・メカニカル・データ
発注情報

7.3.4 Noise Performance

Figure 7-1 shows the total circuit noise for varying source impedances with the operational amplifier in a unity-gain configuration (with no feedback resistor network and therefore no additional noise contributions). The OPA140 and OPA211 are shown with total circuit noise calculated. The op amp contributes both a voltage noise component and a current noise component. The voltage noise is commonly modeled as a time-varying component of the offset voltage. The current noise is modeled as the time-varying component of the input bias current and reacts with the source resistance to create a voltage component of noise. Therefore, the lowest noise op amp for a given application depends on the source impedance. For low source impedance, current noise is negligible, and voltage noise generally dominates. The OPAx140 family has both low voltage noise and extremely low current noise because of the FET input of the op amp. As a result, the current noise contribution of the OPAx140 series is negligible for any practical source impedance, which makes these devices the better choice for applications with high source impedance.

The equation in Figure 7-1 shows the calculation of the total circuit noise, with these parameters:

  • en = voltage noise
  • In = current noise
  • RS = source impedance
  • k = Boltzmann's constant = 1.38 × 10–23 J/K
  • T = temperature in kelvins (K)

For more details on calculating noise, see Section 7.3.5.

GUID-55797506-32C6-441D-BD4A-561740DF1278-low.gifFigure 7-1 Noise Performance of the OPA140 and OPA211 in Unity-Gain Buffer Configuration