SBOS981J October   2019  – April 2021 OPA2607 , OPA607

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Device Comparison
  6. 6 Pin Configuration and Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Operating Voltage
      2. 8.3.2 Rail-to-Rail Output and Driving Capacitive Loads
      3. 8.3.3 Input and ESD Protection
      4. 8.3.4 Decompensated Architecture with Wide Gain-Bandwidth Product
    4. 8.4 Device Functional Modes
      1. 8.4.1 Normal Operating Mode
      2. 8.4.2 Power Down Mode
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Applications
      1. 9.2.1 100-kΩ Gain Transimpedance Design
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
        3. 9.2.1.3 Application Curves
      2. 9.2.2 Noninverting Gain of 3 V/V
      3. 9.2.3 High-Input Impedance (Hi-Z), High-Gain Signal Front-End
        1. 9.2.3.1 Design Requirements
        2. 9.2.3.2 Detailed Design Procedure
        3. 9.2.3.3 Application Curves
      4. 9.2.4 Low-Cost, Low Side, High-Speed Current Sensing
        1. 9.2.4.1 Design Requirements
        2. 9.2.4.2 Detailed Design Procedure
        3. 9.2.4.3 Application Curves
      5. 9.2.5 Ultrasonic Flow Meters
        1. 9.2.5.1 Design Requirements
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Examples
  12. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 Development Support
    2. 12.2 Documentation Support
      1. 12.2.1 Related Documentation
    3. 12.3 Related Links
    4. 12.4 Receiving Notification of Documentation Updates
    5. 12.5 Support Resources
    6. 12.6 Trademarks
    7. 12.7 Electrostatic Discharge Caution
    8. 12.8 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

9.2.2 Noninverting Gain of 3 V/V

The OPAx607 devices are normally stable in noise gain configurations (see SBOA066) of greater than 6 V/V when conventional feedback networks are used, which is discussed in Section 8.3.4. The OPAx607 devices can be configured in noise gains of less than 6 V/V by using capacitors in the feedback path and between the inputs to maintain the desired gain at lower frequencies and increase the gain greater that 6 V/V at higher frequencies such that the amplifier is stable. Configuration (a) in Figure 9-6 shows OPAx607 devices configured in a gain of 3 V/V by using capacitors and resistors to shape the noise gain and achieve a phase margin of approximately 56° that is very close to the phase margin achieved for the conventional 6 V/V configuration (b) in Figure 9-6.

The key benefit of using a decompensated amplifier (such as the OPAx607) below the minimum stable gain, is that it takes advantage of the low noise and low distortion performance at quiescent powers smaller than comparable unity-gain stable architectures. By reducing the 100-pF input capacitor, higher closed-loop bandwidth can be achieved at the expense of increased peaking and reduced phase margin. Ensure that low parasitic capacitance layout techniques on the IN– pin are as small as 1 pF to 2 pF of parasitic capacitance on the inverting input, which will require tweaking the noise-shaping component values to get a flat frequency response and the desired phase margin. Configurations in Figure 9-6 does not take into account this parasitic capacitance but it must be considered for practical purposes. Details on the benefits of decompensated architectures are discussed in Using a decompensated op amp for improved performance. The one-capacitor, externally compensated type method is used for noise gain shaping in the below circuit.

In a difference amplifier circuit, typically used for low side current sensing applications, the (noise gain) = (signal gain + 1).

GUID-FBC92DE6-8457-4A9C-ABA0-8B34B540EBA8-low.gifFigure 9-6 Noninverting Gain of 3 V/V, 6 V/V Configurations and Difference Amplifier in Signal Gain of 2 V/V
GUID-20201016-CA0I-SPLM-XWKB-JHVBQKW9V84D-low.gifFigure 9-7 Small-Signal Frequency Response in Gains of 3V/V (a) and 6V/V (b)
GUID-20201016-CA0I-LD9Q-XMD4-39JDV2T7PJZP-low.gifFigure 9-8 Small-Signal Frequency Response of Difference Amplifier (c) With and Without Noise Gain Shaping