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

8.1 Overview

The ultra-wide, 5.5-GHz gain bandwidth product (GBWP) of the OPA858, combined with the broadband voltage noise of 2.5 nV/√Hz, produces a viable amplifier for wideband transimpedance applications, high-speed data acquisition systems, and applications with weak signal inputs that require low-noise and high-gain front ends. The OPA858 combines multiple features to optimize dynamic performance. In addition to the wide, small-signal bandwidth, the OPA858 has 600 MHz of large-signal bandwidth (VOUT = 2 VPP), and a slew rate of 2000 V/µs.

The OPA858 is offered in a 2-mm × 2-mm, 8-pin WSON package that features a feedback (FB) pin for a simple feedback network connection between the amplifiers output and inverting input. Excess capacitance on an amplifiers input pin can reduce phase margin causing instability. This problem is exacerbated in the case of very wideband amplifiers like the OPA858. To reduce the effects of stray capacitance on the input node, the OPA858 pinout features an isolation pin (NC) between the feedback and inverting input pins that increases the physical spacing between them, thereby reducing parasitic coupling at high frequencies. The OPA858 also features a very low capacitance input stage with only 0.8-pF of total input capacitance.