SLUSD53G March   2018  – August 2020 TPS23880

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Device Comparison Table
  6. 6 Pin Configuration and Functions
    1.     Pin Functions
    2. 6.1 Detailed Pin Description
  7. 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
    6. 7.6 Typical Characteristics
  8. 8 Parameter Measurement Information
    1. 8.1 Timing Diagrams
  9. 9 Detailed Description
    1. 9.1 Overview
      1. 9.1.1 Operating Modes
        1. 9.1.1.1 Auto
        2. 9.1.1.2 Semiauto
        3. 9.1.1.3 Manual/Diagnostic
        4. 9.1.1.4 Power Off
      2. 9.1.2 PoE Compliance Terminology
      3. 9.1.3 Channel versus Port Terminology
      4. 9.1.4 Requested Class versus Assigned Class
      5. 9.1.5 Power Allocation and Power Demotion
      6. 9.1.6 Programmable SRAM
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1 Port Remapping
      2. 9.3.2 Port Power Priority
      3. 9.3.3 Analog-to-Digital Converters (ADC)
      4. 9.3.4 I2C Watchdog
      5. 9.3.5 Current Foldback Protection
    4. 9.4 Device Functional Modes
      1. 9.4.1 Detection
      2. 9.4.2 Connection Check
      3. 9.4.3 Classification
      4. 9.4.4 DC Disconnect
    5. 9.5 I2C Programming
      1. 9.5.1 I2C Serial Interface
    6. 9.6 Register Maps
      1. 9.6.1 Complete Register Set
      2. 9.6.2 Detailed Register Descriptions
        1. 9.6.2.1  INTERRUPT Register
        2. 9.6.2.2  INTERRUPT MASK Register
        3. 9.6.2.3  POWER EVENT Register
        4. 9.6.2.4  DETECTION EVENT Register
        5. 9.6.2.5  FAULT EVENT Register
        6. 9.6.2.6  START/ILIM EVENT Register
        7. 9.6.2.7  SUPPLY and FAULT EVENT Register
          1. 9.6.2.7.1 Detected SRAM Faults and "Safe Mode"
        8. 9.6.2.8  CHANNEL 1 DISCOVERY Register
        9. 9.6.2.9  CHANNEL 2 DISCOVERY Register
        10. 9.6.2.10 CHANNEL 3 DISCOVERY Register
        11. 9.6.2.11 CHANNEL 4 DISCOVERY Register
        12. 9.6.2.12 POWER STATUS Register
        13. 9.6.2.13 PIN STATUS Register
        14. 9.6.2.14 OPERATING MODE Register
        15. 9.6.2.15 DISCONNECT ENABLE Register
        16. 9.6.2.16 DETECT/CLASS ENABLE Register
        17. 9.6.2.17 Power Priority / 2Pair PCUT Disable Register Name
        18. 9.6.2.18 TIMING CONFIGURATION Register
        19. 9.6.2.19 GENERAL MASK Register
        20. 9.6.2.20 DETECT/CLASS RESTART Register
        21. 9.6.2.21 POWER ENABLE Register
        22. 9.6.2.22 RESET Register
        23. 9.6.2.23 ID Register
        24. 9.6.2.24 Connection Check and Auto Class Status Register
        25. 9.6.2.25 2-Pair Police Ch-1 Configuration Register
        26. 9.6.2.26 2-Pair Police Ch-2 Configuration Register
        27. 9.6.2.27 2-Pair Police Ch-3 Configuration Register
        28. 9.6.2.28 2-Pair Police Ch-4 Configuration Register
        29. 9.6.2.29 Power-on Fault Register
        30. 9.6.2.30 PORT RE-MAPPING Register
        31. 9.6.2.31 Channels 1 and 2 Multi Bit Priority Register
        32. 9.6.2.32 Channels 3 and 4 Multi Bit Priority Register
        33. 9.6.2.33 4-Pair Wired and Port Power Allocation Register
        34. 9.6.2.34 4-Pair Police Ch-1 and 2 Configuration Register
        35. 9.6.2.35 4-Pair Police Ch-3 and 4 Configuration Register
        36. 9.6.2.36 TEMPERATURE Register
        37. 9.6.2.37 4-Pair Fault Configuration Register
        38. 9.6.2.38 INPUT VOLTAGE Register
        39. 9.6.2.39 CHANNEL 1 CURRENT Register
        40. 9.6.2.40 CHANNEL 2 CURRENT Register
        41. 9.6.2.41 CHANNEL 3 CURRENT Register
        42. 9.6.2.42 CHANNEL 4 CURRENT Register
        43. 9.6.2.43 CHANNEL 1 VOLTAGE Register
        44. 9.6.2.44 CHANNEL 2 VOLTAGE Register
        45. 9.6.2.45 CHANNEL 3 VOLTAGE Register
        46. 9.6.2.46 CHANNEL 4 VOLTAGE Register
        47. 9.6.2.47 2x FOLDBACK SELECTION Register
        48.       95
        49. 9.6.2.48 FIRMWARE REVISION Register
        50. 9.6.2.49 I2C WATCHDOG Register
        51. 9.6.2.50 DEVICE ID Register
        52. 9.6.2.51 CHANNEL 1 DETECT RESISTANCE Register
        53. 9.6.2.52 CHANNEL 2 DETECT RESISTANCE Register
        54. 9.6.2.53 CHANNEL 3 DETECT RESISTANCE Register
        55. 9.6.2.54 CHANNEL 4 DETECT RESISTANCE Register
        56. 9.6.2.55 CHANNEL 1 ASSIGNED CLASS Register
        57. 9.6.2.56 CHANNEL 2 ASSIGNED CLASS Register
        58. 9.6.2.57 CHANNEL 3 ASSIGNED CLASS Register
        59. 9.6.2.58 CHANNEL 4 ASSIGNED CLASS Register
        60. 9.6.2.59 AUTO CLASS CONTROL Register
        61. 9.6.2.60 CHANNEL 1 AUTO CLASS POWER Register
        62. 9.6.2.61 CHANNEL 2 AUTO CLASS POWER Register
        63. 9.6.2.62 CHANNEL 3 AUTO CLASS POWER Register
        64. 9.6.2.63 CHANNEL 4 AUTO CLASS POWER Register
        65. 9.6.2.64 ALTERNATIVE FOLDBACK Register
        66. 9.6.2.65 SRAM CONTROL Register
          1. 9.6.2.65.1 SRAM START ADDRESS (LSB) Register
          2. 9.6.2.65.2 SRAM START ADDRESS (MSB) Register
          3. 9.6.2.65.3 116
  10. 10Application and Implementation
    1. 10.1 Application Information
      1. 10.1.1 Introduction to PoE
        1. 10.1.1.1 2-Pair Versus 4-Pair Power and the New IEEE802.3bt Standard
    2. 10.2 Typical Application
      1. 10.2.1 Design Requirements
      2. 10.2.2 Detailed Design Procedure
        1. 10.2.2.1 Connections on Unused Channels
        2. 10.2.2.2 Power Pin Bypass Capacitors
        3. 10.2.2.3 Per Port Components
        4. 10.2.2.4 System Level Components (not shown in the schematic diagrams)
      3. 10.2.3 Application Curves
  11. 11Power Supply Recommendations
    1. 11.1 VDD
    2. 11.2 VPWR
  12. 12Layout
    1. 12.1 Layout Guidelines
      1. 12.1.1 Kelvin Current Sensing Resistors
    2. 12.2 Layout Example
      1. 12.2.1 Component Placement and Routing Guidelines
        1. 12.2.1.1 Power Pin Bypass Capacitors
        2. 12.2.1.2 Per-Port Components
  13. 13Device and Documentation Support
    1. 13.1 Documentation Support
      1. 13.1.1 Related Documentation
    2. 13.2 Receiving Notification of Documentation Updates
    3. 13.3 Support Resources
    4. 13.4 Trademarks
    5. 13.5 Electrostatic Discharge Caution
    6. 13.6 Glossary
  14. 14Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

9.6.2.35 4-Pair Police Ch-3 and 4 Configuration Register

COMMAND = 2Bh with 1 Data Byte, Read/Write

Figure 9-42 4-Pair Police Ch-3 and 4 Configuration Register Format
76543210
POL34_7POL34_6POL34_5POL34_4POL34_3POL34_2POL34_1POL34_0
R/W-1R/W-1R/W-1R/W-1R/W-1R/W-1R/W-1R/W1
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 9-44 4-Pair Police Register Field Descriptions
BitFieldTypeResetDescription
7–0POLnn_7- POLnn_0R/W11-byte defining the summed 4-Pair PCUT minimum threshold.

The equation defining the PCUT is:

PCUT = (N × PCSTEP)

Where, when assuming 0.255-Ω Rsense resistor is used:

PCSTEP = 0.5 W

Note:

These bits set the minimum threshold for the design. Internally, the typical PCUT threshold is set slightly above this value to ensure that the device does not trip a Pcut fault at or below the set value in this register due to part to part or temperature variation.

For 4-pair wired, the 2P Policing values are still applied to the individual Channels. See the description for registers 0x1Eh through 0x21h for more information on 2-Pair Policing.

The contents of this register is reset to 0xFFh anytime the port is turned off or disabled either due to fault condition or user command

4-Pair Power Policing:

The TPS23880 implements a true Power Policing limit, where the device will adjust the policing limit based on both voltage and sum of current variation in order to ensure a reliable power limit.

In Semi Auto and Auto modes, these bits are automatically set during power on based on the assigned class (see Table 9-45). If an alternative value is desired, it needs to be set after the PEn bit is set in register 0x10h.

Table 9-45 4-Pair Policing Settings for 4-Pair Wired Port with Single Signature Devices
Assigned ClassPOLnn7-0 SettingsMinimum Power
Class 10000 10004W
Class 20000 11107W
Class 30001 111115.5W
Class 40011 110030W
Class 50101 101045W
Class 60111 100060W
Class 71001 011075W
Class 81011 010090W

For a 4-pair dual signature devices, these values will be set based on the sum of the assigned classes of both channels, but 4P PCut will be disabled (4PPCTnn bit in 0x2D = 0) by default as the primary policing method for dual signature devices will be the 2-Pair values defined in registers 0x1Eh - 0x21h.

Setting the 4PPCTnn bit in 0x2D will enable 4P Policing if desired.