JAJU648A November   2018  – April 2022 TLV3601 , TLV3601-Q1 , TLV3603 , TLV3603-Q1

 

  1.   概要
  2.   Resources
  3.   特長
  4.   アプリケーション
  5.   5
  6. 1System Description
    1. 1.1 Key System Specifications
  7. 2System Overview
    1. 2.1 Block Diagram
    2. 2.2 Design Considerations
      1. 2.2.1 Amplifier and Comparator
      2. 2.2.2 Digital Processing and Control
      3. 2.2.3 Optical Components
        1. 2.2.3.1 Laser Driver and Laser Diode
        2. 2.2.3.2 Photodiode
      4. 2.2.4 Power Supply
    3. 2.3 Highlighted Products
      1. 2.3.1 OPA858 Operational Amplifier
      2. 2.3.2 TLV3501 and TLV3601/3 High-Speed Comparators
      3. 2.3.3 TDC7201 Time-to-Digital Converter
    4. 2.4 System Design Theory
      1. 2.4.1 Transimpedance Amplifier
        1. 2.4.1.1 Bandwidth
        2. 2.4.1.2 Stability Considerations
        3. 2.4.1.3 Noise Performance
      2. 2.4.2 Time-of-Flight Measurement
      3. 2.4.3 Simulations
        1. 2.4.3.1 Bandwidth Simulation
        2. 2.4.3.2 Noise Simulation
        3. 2.4.3.3 OPA858 Loop-Gain and Phase Margin Simulation
  8. 3Hardware, Software, Testing Requirements, and Test Results
    1. 3.1 Required Hardware and Software
      1. 3.1.1 Hardware
      2. 3.1.2 Software
    2. 3.2 Testing and Results
      1. 3.2.1 Test Setup
        1. 3.2.1.1 Getting Started: System Setup
          1. 3.2.1.1.1 Laser-Driver Setup
          2. 3.2.1.1.2 Receiver and Optical Setup
      2. 3.2.2 Test Results
        1. 3.2.2.1 Verification and Measured Performance
          1. 3.2.2.1.1 Pulse Response Measurements
            1. 3.2.2.1.1.1 Pulse Response Settling
            2. 3.2.2.1.1.2 Pulse Response vs Output Pulse Width
            3. 3.2.2.1.1.3 Rise and Fall Time
            4. 3.2.2.1.1.4 Overdriven Response
          2. 3.2.2.1.2 Time-of-Flight Test
          3. 3.2.2.1.3 Time-of-Flight Measurement Error Sources
  9. 4Design Files
    1. 4.1 Schematics
    2. 4.2 Bill of Materials
    3. 4.3 PCB Layout Recommendations
      1. 4.3.1 Layout Prints
    4. 4.4 Altium Project
    5. 4.5 Gerber Files
  10. 5Related Documentation
    1. 5.1 Trademarks
  11. 6About the Author
  12. 7Revision History

2.4.1.2 Stability Considerations

As with any high-speed amplifier design, always pay attention to the stability of the circuit. The OPA858 is a decompensated amplifier that is only stable at noise gains of 7 V/V or higher and can oscillate at lower gains. Decompensated amplifiers are a natural fit for transimpedance circuits because the combination of input capacitance and feedback capacitance form the high-frequency gain value at the point where the noise gain of the circuit intersects with the open-loop gain from the amplifier (this point is also the reference point for the phase margin measurement). With the input capacitance and selected feedback capacitor for the circuit, the noise gain measured at the open-loop gain (Aol) crossing point is approximately 20 V/V, which is far higher than required for stability.