SBOS701D December   2015  – August 2021 OPA191 , OPA2191 , OPA4191

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information: OPA191
    5. 6.5 Thermal Information: OPA2191
    6. 6.6 Thermal Information: OPA4191
    7. 6.7 Electrical Characteristics: VS = ±4 V to ±18 V (VS = 8 V to 36 V)
    8. 6.8 Electrical Characteristics: VS = ±2.25 V to ±4 V (VS = 4.5 V to 8 V)
    9. 6.9 Typical Characteristics
  7. 7 Parameter Measurement Information
    1. 7.1 Input Offset Voltage Drift
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Input Protection Circuitry
      2. 8.3.2 EMI Rejection
      3. 8.3.3 Phase Reversal Protection
      4. 8.3.4 Thermal Protection
      5. 8.3.5 Capacitive Load and Stability
      6. 8.3.6 Common-Mode Voltage Range
      7. 8.3.7 Electrical Overstress
      8. 8.3.8 Overload Recovery
    4. 8.4 Device Functional Modes
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Applications
      1. 9.2.1 Low-side Current Measurement
        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 16-Bit Precision Multiplexed Data-Acquisition System
        1. 9.2.2.1 Design Requirements
        2. 9.2.2.2 Detailed Design Procedure
      3. 9.2.3 Slew Rate Limit for Input Protection
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 Development Support
        1. 12.1.1.1 TINA-TI™ SImulation Software (Free Download)
        2. 12.1.1.2 TI Precision Designs
    2. 12.2 Documentation Support
      1. 12.2.1 Related Documentation
    3. 12.3 Receiving Notification of Documentation Updates
    4. 12.4 Support Resources
    5. 12.5 Trademarks
    6. 12.6 Electrostatic Discharge Caution
    7. 12.7 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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

8.3.1 Input Protection Circuitry

The OPAx191 uses a unique input architecture to eliminate the need for input protection diodes but still provides robust input protection under transient conditions. Conventional input diode protection schemes shown in Figure 8-1 can be activated by fast transient step responses and can introduce signal distortion and settling time delays because of alternate current paths, as shown in Figure 8-2. For low-gain circuits, these fast-ramping input signals forward-bias back-to-back diodes that cause an increase in input current, resulting in extended settling time.

GUID-6ACB3C95-BEF6-4AB3-81E5-B8471953D194-low.gifFigure 8-1 OPA191 Input Protection Does Not Limit Differential Input Capability
GUID-74027EC2-3BBF-4CDE-BCBE-560DD04A1A65-low.gifFigure 8-2 Back-to-Back Diodes Create Settling Issues

The OPAx191 family of operational amplifiers provides a true high-impedance differential input capability for high-voltage applications. This patented input protection architecture does not introduce additional signal distortion or delayed settling time, making the device an optimal op amp for multichannel, high-switched, input applications. The OPAx191 tolerates a maximum differential swing (voltage between inverting and noninverting pins of the op amp) of up to 36 V, making the device an excellent choice for use as a comparator or in applications with fast-ramping input signals such as multiplexed data-acquisition systems (see Figure 9-4).