SBOSA51 December   2020 THS4567

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
    5. 6.5 Electrical Characteristics: Differential TIA Mode, ICM loop enabled
    6. 6.6 Electrical Characteristics: FDA operation, ICM loop disabled
    7. 6.7 Typical Characteristics: (VS+) – (VS–) = 5 V
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Main Amplifier
      2. 7.3.2 Output Common-Mode Control
      3. 7.3.3 Input Common-Mode Control
    4. 7.4 Device Functional Modes
      1. 7.4.1 Shutdown Mode
      2. 7.4.2 Differential Transimpedance Amplifier Mode
      3. 7.4.3 Fully Differential Amplifier (FDA) Mode
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Noise Analysis
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure (THS4567 in TIA Mode)
        1. 8.2.2.1 OPA Mode Configuration
      3. 8.2.3 Application Curves
    3. 8.3 Differential TIA with 0-V Biased Photodiode
    4. 8.4 Differential AC Coupled TIA
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
      1. 10.1.1 Board Layout Recommendations
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Related Documentation
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Support Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

7.3.2 Output Common-Mode Control

The output common-mode loop works by sensing the average voltage between the two outputs of the main amplifier through the two 6-kΩ resistors internal resistors in Section 7.2 and comparing it against the voltage at the VOCM pin. The VOCM error amplifier then adjusts the internal bias of the main amplifier to minimize the error voltage between its input pins. The voltage at the VOCM node defaults to midsupply through the two 400-kΩ internal bias string resistors between VS+ and VS–. When using the VOCM at its default voltage, connect an external capacitor to the VOCM pin to bypass the noise from the internal 400-kΩ resistors. When the amplifier is disabled, the default midsupply bias string is disabled to save power. The THS4567 device output common-mode can also be set by driving the VOCM pin externally through a low output impedance source. Ensure that the source is capable of driving the input impedance of the VOCM pin.