SNLA224A June   2014  – January 2024 DS90UB913A-Q1 , DS90UB954-Q1 , DS90UB960-Q1

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2Theory of Operation for Power Over Coax
    1. 2.1 Inductor Characteristics
    2. 2.2 Capacitor Characteristics
    3. 2.3 Ferrite Bead Characteristics
  6. 3Design Considerations
    1. 3.1 Frequency Range
    2. 3.2 Power Considerations
    3. 3.3 Inductor Size Considerations
    4. 3.4 Layout Considerations
  7. 4FPD-Link PoC Requirements
    1. 4.1 Channel Requirements
    2. 4.2 PoC Noise Requirements
      1. 4.2.1 VPoC Noise and Pulse
      2. 4.2.2 RIN+ Noise
      3. 4.2.3 Causes of PoC Noise
      4. 4.2.4 Noise Measurement Best Practices
      5. 4.2.5 Reducing Effects of PoC Noise
  8. 5TI Recommended PoC Networks
    1. 5.1 PoC Network From FPD-Link III Data Sheet
    2. 5.2 Murata Networks
      1. 5.2.1 Murata Network 1
      2. 5.2.2 Murata Network 2
      3. 5.2.3 Murata Network 3
    3. 5.3 TDK Networks
      1. 5.3.1 TDK Network 1
      2. 5.3.2 TDK Network 2
      3. 5.3.3 TDK Network 3
      4. 5.3.4 TDK Network 4
      5. 5.3.5 TDK Network 5
      6. 5.3.6 TDK Network 6
      7. 5.3.7 TDK Network 7
      8. 5.3.8 TDK Network 8
    4. 5.4 Coilcraft Networks
      1. 5.4.1 Coilcraft Network 1
      2. 5.4.2 Coilcraft Network 2
      3. 5.4.3 Coilcraft Network 3
      4. 5.4.4 Coilcraft Network 4
  9. 6Summary
  10. 7References
  11. 8Revision History

Power Considerations

Each PoC network has a maximum current rating based on the saturation characteristics of the components. As discussed in Section 2.1, inductors saturate, dissipate heat, and pass very high frequencies when the maximum current rating is not respected. The individual operating specifications of every PoC component must be followed to provide proper filtering.

The PoC network must have a current rating that allows for an appropriate amount of power to be supplied to the serializer and sensor. The maximum power drawn by the serializer board can be calculated from the worst-case scenario power consumption of the serializer side of the link. An example of a potential maximum power consumption scenario is a period where the sensor is actively gathering data and all other remote devices are operating. Please note that the worst-case scenario and maximum power consumption is system dependent and can vary across designs. The IR drop due to the parasitic impedance of the individual components and cables must also be considered. TI recommends several different PoC networks capable of different levels of power delivery. The chosen PoC network must be capable of supplying enough current and power from the given PoC voltage for the serializer and sensor.