ZHCSMU0D July   2009  – December 2020 TPS23753A

PRODUCTION DATA  

  1. 特性
  2. 应用
  3. 说明
  4. Revision History
  5. Product Information
  6. Pin Configuration and Functions
  7. Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics: Controller Section Only
    6. 7.6 Electrical Characteristics: PoE and Control
    7. 7.7 Typical Characteristics
  8. Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Pin Description
        1. 8.3.1.1  APD
        2. 8.3.1.2  BLNK
        3. 8.3.1.3  CLS
        4. 8.3.1.4  CS
        5. 8.3.1.5  CTL
        6. 8.3.1.6  DEN
        7. 8.3.1.7  FRS
        8. 8.3.1.8  GATE
        9. 8.3.1.9  RTN
        10. 8.3.1.10 VB
        11. 8.3.1.11 VC
        12. 8.3.1.12 VDD
        13. 8.3.1.13 VDD1
        14. 8.3.1.14 VSS
    4. 8.4 Device Functional Modes
      1. 8.4.1  Threshold Voltages
      2. 8.4.2  PoE Start-Up Sequence
      3. 8.4.3  Detection
      4. 8.4.4  Hardware Classification
      5. 8.4.5  Maintain Power Signature (MPS)
      6. 8.4.6  TPS23753A Operation
        1. 8.4.6.1 Start-Up and Converter Operation
        2. 8.4.6.2 PD Self-Protection
        3. 8.4.6.3 Converter Controller Features
      7. 8.4.7  Special Switching MOSFET Considerations
      8. 8.4.8  Thermal Considerations
      9. 8.4.9  FRS and Synchronization
      10. 8.4.10 Blanking – RBLNK
      11. 8.4.11 Current Slope Compensation
      12. 8.4.12 Adapter ORing
      13. 8.4.13 Protection
      14. 8.4.14 Frequency Dithering for Conducted Emissions Control
  9. Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
      3. 9.2.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Documentation Support
      1. 12.1.1 Related Documentation
    2. 12.2 Support Resources
    3. 12.3 Electrostatic Discharge Caution
    4. 12.4 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

APD

APD forces power to come from an external adapter connected from VDD1 to RTN by opening the hotswap switch. TI recommends using a resistor divider. The divider provides ESD protection, leakage discharge for the adapter ORing diode, and input voltage qualification. Voltage qualification assures the adapter can support the PD before the PoE current is cut off.

Select the APD divider resistors per Equation 1 and Equation 2, where VADPTR-ON is the desired adapter voltage that enables the APD function as adapter voltage rises.

Equation 1. GUID-2C318E95-B6B4-4D97-89FE-EF95EA2AA3E7-low.gif
Equation 2. GUID-6CF2B997-831F-456F-A3BB-E68DB1F96ADA-low.gif

The CLS output is disabled when a voltage above VAPDEN is applied to the APD pin.

Place the APD pulldown resistor adjacent to the APD pin.

APD must be tied to RTN when not used.