JAJSFG2I December   2013  – May 2018 OPA172 , OPA2172 , OPA4172

PRODUCTION DATA.  

  1. 1 特長
  2. 2 アプリケーション
  3. 3 概要
    1.     Device Images
      1.      JFET入力の低ノイズ・アンプ
      2.      優れたTHD性能
  4. 4 改訂履歴
  5. 5 概要（続き）
  6. 6 Device Comparison
    1. 6.1 Device Comparison
    2. 6.2 Device Family Comparison
  7. 7 Pin Configuration and Functions
    1.     Pin Functions: OPA172
    2.     Pin Functions: OPA2172 and OPA4172
  8. 8 Specifications
    1. 8.1 Absolute Maximum Ratings
    2. 8.2 ESD Ratings
    3. 8.3 Recommended Operating Conditions
    4. 8.4 Thermal Information: OPA172
    5. 8.5 Thermal Information: OPA2172
    6. 8.6 Thermal Information: OPA4172
    7. 8.7 Electrical Characteristics
    8. 8.8 Typical Characteristics: Table of Graphs
    9. 8.9 Typical Characteristics
  9. 9 Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1 EMI Rejection
      2. 9.3.2 Phase-Reversal Protection
      3. 9.3.3 Capacitive Load and Stability
    4. 9.4 Device Functional Modes
      1. 9.4.1 Common-Mode Voltage Range
      2. 9.4.2 Electrical Overstress
      3. 9.4.3 Overload Recovery
  10. 10Applications and Implementation
    1. 10.1 Application Information
    2. 10.2 Typical Applications
      1. 10.2.1 Capacitive Load Drive Solution Using an Isolation Resistor
        1. 10.2.1.1 Design Requirements
        2. 10.2.1.2 Detailed Design Procedure
        3. 10.2.1.3 Application Curve
      2. 10.2.2 Bidirectional Current Source
      3. 10.2.3 JFET-Input Low-Noise Amplifier
  11. 11Power-Supply Recommendations
  12. 12Layout
    1. 12.1 Layout Guidelines
    2. 12.2 Layout Example
  13. 13デバイスおよびドキュメントのサポート
    1. 13.1 デバイス・サポート
      1. 13.1.1 開発サポート
        1. 13.1.1.1 TINA-TI(無料のダウンロード・ソフトウェア)
    2. 13.2 ドキュメントのサポート
      1. 13.2.1 関連資料
    3. 13.3 関連リンク
    4. 13.4 コミュニティ・リソース
    5. 13.5 商標
    6. 13.6 静電気放電に関する注意事項
    7. 13.7 Glossary
  14. 14メカニカル、パッケージ、および注文情報

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

10.2.2 Bidirectional Current Source

The improved Howland current-pump topology shown in Figure 50 provides excellent performance because of the extremely tight tolerances of the on-chip resistors of the INA132. By buffering the output using an OPA172, the output current the circuit is able to deliver is greatly extended.

The circuit dc transfer function is shown in Equation 2:

Equation 2. IOUT = VIN / R1

The OPA172 can also be used as the feedback amplifier because the low bias current minimizes error voltages produced across R1. However, for improved performance, select a FET-input device with extremely low offset, such as the OPA192, OPA140, or OPA188 as the feedback amplifier.

OPA172 OPA2172 OPA4172 ai_bidir_Isource_bos618.gifFigure 50. Bidirectional Current Source