SLUSC25A February   2015  – August 2017 TPS2388

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Simplified Schematic
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin Functions
    2. 5.1 Detailed Pin Description
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Timing Requirements
    7. 6.7 Switching Characteristics
    8. 6.8 Typical Characteristics
  7. 7 Parameter Measurement Information
    1. 7.1 Timing Diagrams
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Port Remapping
      2. 8.3.2 Port Power Priority
      3. 8.3.3 A/D Converter
      4. 8.3.4 I2C Watchdog
      5. 8.3.5 Foldback Protection
    4. 8.4 Device Functional Modes
      1. 8.4.1 Port Operating Modes
        1. 8.4.1.1 Semiauto
        2. 8.4.1.2 Manual
        3. 8.4.1.3 Power Off
      2. 8.4.2 Detection
      3. 8.4.3 Classification
      4. 8.4.4 DC Disconnect
    5. 8.5 Programming
      1. 8.5.1 I2C Serial Interface
    6. 8.6 Register Maps
      1. 8.6.1  Complete Register Set
      2. 8.6.2  INTERRUPT Register
        1. Table 4. INTERRUPT Register Field Descriptions
      3. 8.6.3  INTERRUPT MASK Register
        1. Table 5. INTERRUPT MASK Register Field Descriptions
      4. 8.6.4  POWER EVENT Register
        1. Table 6. POWER EVENT Register Field Descriptions
      5. 8.6.5  DETECTION EVENT Register
        1. Table 7. DETECTION EVENT Register Field Descriptions
      6. 8.6.6  FAULT EVENT Register
        1. Table 8. FAULT EVENT Register Field Descriptions
      7. 8.6.7  START/ILIM EVENT Register
        1. Table 9. START/ILIM EVENT Register Field Descriptions
      8. 8.6.8  SUPPLY EVENT Register
        1. Table 10. SUPPLY EVENT Register Field Descriptions
      9. 8.6.9  PORT 1 STATUS Register
      10. 8.6.10 PORT 2 STATUS Register
      11. 8.6.11 PORT 3 STATUS Register
      12. 8.6.12 PORT 4 STATUS Register
        1. Table 11. PORT STATUS Register Field Descriptions
      13. 8.6.13 POWER STATUS Register
        1. Table 12. POWER STATUS Register Field Descriptions
      14. 8.6.14 Pin Status Register
        1. Table 13. Pin Status Register Field Descriptions
      15. 8.6.15 OPERATING MODE Register
        1. Table 14. OPERATING MODE Register Field Descriptions
      16. 8.6.16 DISCONNECT ENABLE Register
        1. Table 15. DISCONNECT ENABLE Register Field Descriptions
      17. 8.6.17 DETECT/CLASS ENABLE Register
        1. Table 16. DETECT/CLASS ENABLE Register Field Descriptions
      18. 8.6.18 Port Power Priority/ICUT Disable Register Name
        1. Table 17. Port Power Priority/ICUT Disable Register Field Descriptions
      19. 8.6.19 TIMING CONFIGURATION Register
        1. Table 18. TIMING CONFIGURATION Register Field Descriptions
      20. 8.6.20 GENERAL MASK Register
        1. Table 19. GENERAL MASK Register Field Descriptions
      21. 8.6.21 DETECT/CLASS RESTART Register
        1. Table 20. DETECT/CLASS RESTART Register Field Descriptions
      22. 8.6.22 POWER ENABLE Register
        1. Table 21. POWER ENABLE Register Field Descriptions
      23. 8.6.23 RESET Register
        1. Table 22. RESET Register Field Descriptions
      24. 8.6.24 ID Register
        1. Table 23. ID Register Field Descriptions
      25. 8.6.25 Police 21 Configuration Register
      26. 8.6.26 Police 43 Configuration Register
        1. Table 24. Police 43 Register Field Descriptions
      27. 8.6.27 IEEE Power Enable Register
        1. Table 25. IEEE Power Enable Register Field Descriptions
      28. 8.6.28 Power-on Fault Register
        1. Table 26. Power-on Fault Register Field Descriptions
      29. 8.6.29 PORT RE-MAPPING Register
        1. Table 27. PORT RE-MAPPING Register Field Descriptions
      30. 8.6.30 Port 21 Multi Bit Priority Register
      31. 8.6.31 Port 43 Multi Bit Priority Register
        1. Table 28. Port 43 Register Field Descriptions
      32. 8.6.32 TEMPERATURE Register
        1. Table 29. TEMPERATURE Register Field Descriptions
      33. 8.6.33 INPUT VOLTAGE Register
        1. Table 30. INPUT VOLTAGE Register Field Descriptions
      34. 8.6.34 PORT 1 CURRENT Register
      35. 8.6.35 PORT 2 CURRENT Register
      36. 8.6.36 PORT 3 CURRENT Register
      37. 8.6.37 PORT 4 CURRENT Register
        1. Table 31. PORT 4 CURRENT Register Field Descriptions
      38. 8.6.38 PORT 1 VOLTAGE Register
      39. 8.6.39 PORT 2 VOLTAGE Register
      40. 8.6.40 PORT 3 VOLTAGE Register
      41. 8.6.41 PORT 4 VOLTAGE Register
        1. Table 32. PORT 4 VOLTAGE Register Field Descriptions
      42. 8.6.42 PoE Plus Register
        1. Table 33. PoE Plus Register Field Descriptions
      43. 8.6.43 FIRMWARE REVISION
        1. Table 34. FIRMWARE REVISION Register Field Descriptions
      44. 8.6.44 I2C WATCHDOG Register
        1. Table 35. I2C WATCHDOG Register Field Descriptions
      45. 8.6.45 DEVICE ID Register
        1. Table 36. DEVICE ID Register Field Descriptions
      46. 8.6.46 PORT 1 DETECT RESISTANCE Register
      47. 8.6.47 PORT 2 DETECT RESISTANCE Register
      48. 8.6.48 PORT 3 DETECT RESISTANCE Register
      49. 8.6.49 PORT 4 DETECT RESISTANCE Register
        1. Table 37. PORT 4 DETECT RESISTANCE Register Field Descriptions
  9. 9 Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 Introduction to PoE
      2. 9.1.2 TPS2388 Application
      3. 9.1.3 Kelvin Current Sensing Resistor
      4. 9.1.4 Connections on Unused Ports
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Power Pin Bypass Capacitors
        2. 9.2.2.2 Per Port Components
        3. 9.2.2.3 System Level Components (not shown in the schematic diagrams)
      3. 9.2.3 Application Curves
  10. 10Power Supply Recommendations
    1. 10.1 VDD
    2. 10.2 VPWR
  11. 11Layout
    1. 11.1 Layout Guidelines
      1. 11.1.1 Port Current Kelvin Sensing
    2. 11.2 Layout Example
      1. 11.2.1 Component Placement and Routing Guidelines
        1. 11.2.1.1 Power Pin Bypass Capacitors
        2. 11.2.1.2 Per-Port Components
  12. 12Device and Documentation Support
    1. 12.1 Receiving Notification of Documentation Updates
    2. 12.2 Community Resources
    3. 12.3 Trademarks
    4. 12.4 Electrostatic Discharge Caution
    5. 12.5 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

8.3.4 I2C Watchdog

An I2C Watchdog timer is available on the TPS2388 device. The timer monitors the I2C, SCL line for clock edges. When enabled, a timeout of the watchdog resets the I2C interface along with any active ports. This feature provides protection in the event of a hung software situation or I2C bus hang-up by slave devices. In the latter case, if a slave is attempting to send a data bit of 0 when the master stops sending clocks, then the slave could get stuck driving the data line low indefinitely. Because the data line is being driven low, the master cannot send a STOP to clean up the bus. Activating the I2C watchdog feature of the TPS2388 would clear this deadlocked condition. If the timer of 2 seconds expires, the ports latch off and the WD Status bit is set. Note that WD Status will be set even if the watchdog is not enabled. WD Status can only be cleared by a reset or writing a 0 to the WDS status bit location. The 4-bit watchdog disable field shuts down this feature when a code of 1011b is loaded. This field is preset to 1011b whenever the TPS2388 is initially powered. Also see I2C WATCHDOG Register for more details.