SBOS629B April   2018  – May 2025 OPA858

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
      5. 8.3.5 Current Noise
    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
      1. 9.1.1 Using the OPA858 as a Transimpedance Amplifier
    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
    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

8.3.4 Slew Rate and Output Stage

In addition to wide bandwidth, the OPA858 features a high slew rate of 2000 V/µs. The slew rate is a critical parameter in high-speed pulse applications with narrow sub-10-ns pulses, such as optical time-domain reflectometry (OTDR) and LIDAR. The high slew rate of the OPA858 implies that the device accurately reproduces a 2-V, sub-ns pulse edge; see also Figure 6-20. The wide bandwidth and slew rate make the OPA858 an excellent amplifier for high-speed signal-chain front ends.

Figure 8-7 shows the open-loop output impedance of the OPA858 as a function of frequency. To achieve high slew rates and low output impedance across frequency, the output swing of the OPA858 is limited to approximately 3 V. The OPA858 is typically used in conjunction with high-speed pipeline ADCs and flash ADCs that have limited input ranges. Therefore, the OPA858 output swing range coupled with the class-leading voltage noise specification for a CMOS amplifier maximizes the overall dynamic range of the signal chain.

OPA858 Open-Loop Output Impedance (ZOL) vs Frequency Figure 8-7 Open-Loop Output Impedance (ZOL) vs Frequency