SBOS622D July   2018  – May 2025 OPA855

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison Table
  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
    5. 6.5 Electrical Characteristics
    6. 6.6 Typical Characteristics
  8. 7 Parameter Measurement Information
  9. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Input and ESD Protection
      2. 8.3.2 Feedback Pin
      3. 8.3.3 Wide Gain-Bandwidth Product
      4. 8.3.4 Slew Rate and Output Stage
    4. 8.4 Device Functional Modes
      1. 8.4.1 Split-Supply and Single-Supply Operation
      2. 8.4.2 Power-Down Mode
  10. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Applications
      1. 9.2.1 TIA in an Optical Front-End System
        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 Optical Sensor Interface
        1. 9.2.2.1 Design Requirements
        2. 9.2.2.2 Detailed Design Procedure
        3. 9.2.2.3 Application Curves
    3. 9.3 Power Supply Recommendations
    4. 9.4 Layout
      1. 9.4.1 Layout Guidelines
      2. 9.4.2 Layout Example
  11. 10Device and Documentation Support
    1. 10.1 Device Support
      1. 10.1.1 Development Support
    2. 10.2 Documentation Support
      1. 10.2.1 Related Documentation
    3. 10.3 Receiving Notification of Documentation Updates
    4. 10.4 Support Resources
    5. 10.5 Trademarks
    6. 10.6 Electrostatic Discharge Caution
    7. 10.7 Glossary
  12. 11Revision History
  13. 12Mechanical, Packaging, and Orderable Information

8.2 Functional Block Diagram

The OPA855 is a classic voltage-feedback operational amplifier (op amp) with two high-impedance inputs and a low-impedance output. Standard application circuits are supported, such as the two basic options in Figure 8-1 and Figure 8-2. The resistor on the noninverting pin is used for bias current cancellation to minimize the output offset voltage. In a noninverting configuration, the additional resistors on the noninverting pin add noise to the system; therefore, if SNR is critical, the resistor can be eliminated. In an inverting configuration, the noninverting node is typically connected to a dc voltage; therefore, the high-frequency noise contribution from the bias cancellation resistor can be bypassed by adding a large 1-µF capacitor in parallel to the resistor to shunt the noise. The dc operating point for each configuration is level-shifted by the reference voltage (VREF), which is typically set to midsupply in single-supply operation. VREF is typically connected to ground in split-supply applications.

OPA855 Noninverting Amplifier Figure 8-1 Noninverting Amplifier
OPA855 Inverting Amplifier Figure 8-2 Inverting Amplifier