TIDUF49 February   2024

 

  1.   1
  2.   Description
  3.   Resources
  4.   Features
  5.   Applications
  6.   6
  7. 1System Description
    1. 1.1 Key System Specifications
  8. 2System Overview
    1. 2.1 System Block Diagram
    2. 2.2 Design Considerations
    3. 2.3 Highlighted Products
      1. 2.3.1 DP83RG720S-Q1 (Automotive SPE PHY)
      2. 2.3.2 TPS1HTC30-Q1 (HSS)
      3. 2.3.3 LM5157x-Q1 and LM5158x-Q1 (PSE PoDL Boost Converter)
      4. 2.3.4 LMR38020-Q1 (PD PoDL Buck Converter)
      5. 2.3.5 TPS629210-Q1 (PD 5.0V Rail Buck Converter)
      6. 2.3.6 TPS746-Q1 (PD PHY 3.3V Rail LDO)
      7. 2.3.7 TPS745-Q1 (PSE and PD PHY 1.0V Rail LDO)
  9. 3System Design Theory
    1. 3.1 System Design Consideration for TIDA-020060 (PSE)
      1. 3.1.1 Ethernet PHY
      2. 3.1.2 PHY Power Supply
      3. 3.1.3 PSE Specific PoDL Power Supply
    2. 3.2 System Design Consideration for TIDA-020061 (PD)
    3. 3.3 General Design Consideration for PoDL Coupling Decoupling Network
  10. 4Hardware, Software, Testing Requirements, and Test Results
    1. 4.1 Hardware Requirements
    2. 4.2 Software Requirements
    3. 4.3 Test Setup
    4. 4.4 Test Results
  11. 5Design and Documentation Support
    1. 5.1 Design Files
      1. 5.1.1 Schematics
      2. 5.1.2 BOM
      3. 5.1.3 PCB Layout Recommendations
    2. 5.2 Tools and Software
    3. 5.3 Documentation Support
    4. 5.4 Support Resources
    5. 5.5 Trademarks
  12. 6About the Author

3.2 System Design Consideration for TIDA-020061 (PD)

GUID-20240213-SS0I-NCRF-TNLB-FRH0B8SLTHKW-low.svg Figure 3-2 TIDA-020061 (PD) board overview

This design includes a buck converter capable of investigating PoDL functionalities in a broad range of use cases. This includes the need for a buck converter family which is able to step down the PoDL voltage down to 12V system voltage rail.

For a final implementation, consider if a buck converter is required or not. Using a buck converter which is optimized for the final application is recommended. In the case where VPoDL= 12V, the output of the CDN can directly be fed into the existing power tree. Consider using one of the buck converters listed in Table 3-2.

Table 3-2 Recommended PD PoDL Buck converter
DEVICE MAXIMUM INPUT VOLTAGE MAXIMUM OUTPUT CURRENT
LM63635-Q1 32V 3.25A
LMQ61460-Q1 36V 6A
LM76003-Q1 60V 3.5A