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

2.3.3 LM5157x-Q1 and LM5158x-Q1 (PSE PoDL Boost Converter)

The LM5157x-Q1 device is a wide input range, nonsynchronous boost converter with integrated 50V, 6.5A (LM5157-Q1) or 50V, 4.33A (LM51571-Q1) power switch. The device can be used in boost, SEPIC, and flyback topologies. The device can start up from a single-cell battery with a minimum of 2.9V. The device can operate with the input supply voltage as low as 1.5V if the BIAS pin is greater than 2.9V.

The LM5158x-Q1 device is a wide input range, nonsynchronous boost converter with an integrated 85V, 3.26A (LM5158-Q1) or 85V, 1.63A (LM51581-Q1) power switch. The device can be used in boost, SEPIC, and flyback topologies. The device can start up from a single-cell battery with a minimum of 3.2V and can operate with the input supply voltage as low as 1.5V if the BIAS pin is greater than 3.2V. The BIAS pin operates up to 60V (65V absolute maximum) for automotive load dump. The switching frequency is dynamically programmable from 100kHz to 2.2MHz with an external resistor. Switching at 2.2MHz minimizes AM band interference and allows for a small design size and fast transient response. The device provides a selectable Dual Random Spread Spectrum to help reduce the EMI over a wide frequency range.