SLLA529 October   2020 ISO7741

 

  1. 1 Introduction
  2. 2 General Considerations
  3. 3 Group-Isolated Analog Input Modules
    1.     Requirements for Digital Isolator in Group-Isolated AI modules:
    2.     Requirements for Isolated Power in Group-Isolated AI modules:
  4. 4 Channel-to-Channel Isolated Analog Input Modules
    1.     Requirements for Digital Isolator in channel-to-channel isolated AI modules
    2.     Requirements for Isolated Power in channel-to-channel isolated AI modules
  5. 5Isolation Products for Analog Input Modules
  6. 6Conclusion
  7. 7References
    1.     Trademarks

Requirements for Isolated Power in Group-Isolated AI modules:

  1. High Efficiency: Depending on the number of analog channels and the complexity of the circuits, the power requirement on the isolated side can be in the range of 0.5 W to 1 W. To reduce the power dissipation in the tightly packed and small form factor modules, and to reduce the current draw from the backplane, the isolated power supply must be very efficient.

  2. Low Electromagnetic Emissions: The cables attached to the AI modules act like transmitting antennas, so the isolated DC-DC must have very low emissions.

  3. Flexible Output Voltage: Depending on the design requirements +/-15 V, +/-5 V or 5 V isolated supply voltage may be needed.