SLVSF02E march   2019  – may 2023 TPS23881

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Revision History
  6. 5 Device Comparison Table
  7. 6 Pin Configuration and Functions
    1. 6.1 Detailed Pin Description
  8. 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
  9. 8 Parameter Measurement Information
    1. 8.1 Timing Diagrams
  10. 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 and 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"
            1. 9.6.2.7.1.1 ULA (Ultra Low Alpha) Package Option: TPS23881A
        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 Capacitance (Legacy PD) Detection
        30. 9.6.2.30 Power-on Fault Register
        31. 9.6.2.31 PORT RE-MAPPING Register
        32. 9.6.2.32 Channels 1 and 2 Multi Bit Priority Register
        33. 9.6.2.33 Channels 3 and 4 Multi Bit Priority Register
        34. 9.6.2.34 4-Pair Wired and Port Power Allocation Register
        35. 9.6.2.35 4-Pair Police Ch-1 and 2 Configuration Register
        36. 9.6.2.36 4-Pair Police Ch-3 and 4 Configuration Register
        37. 9.6.2.37 TEMPERATURE Register
        38. 9.6.2.38 4-Pair Fault Configuration Register
        39. 9.6.2.39 INPUT VOLTAGE Register
        40. 9.6.2.40 CHANNEL 1 CURRENT Register
        41. 9.6.2.41 CHANNEL 2 CURRENT Register
        42. 9.6.2.42 CHANNEL 3 CURRENT Register
        43. 9.6.2.43 CHANNEL 4 CURRENT Register
        44. 9.6.2.44 CHANNEL 1 VOLTAGE Register
        45. 9.6.2.45 CHANNEL 2 VOLTAGE Register
        46. 9.6.2.46 CHANNEL 3 VOLTAGE Register
        47. 9.6.2.47 CHANNEL 4 VOLTAGE Register
        48. 9.6.2.48 2x FOLDBACK SELECTION Register
        49. 9.6.2.49 FIRMWARE REVISION Register
        50. 9.6.2.50 I2C WATCHDOG Register
        51. 9.6.2.51 DEVICE ID Register
        52. 9.6.2.52 CHANNEL 1 DETECT RESISTANCE Register
        53. 9.6.2.53 CHANNEL 2 DETECT RESISTANCE Register
        54. 9.6.2.54 CHANNEL 3 DETECT RESISTANCE Register
        55. 9.6.2.55 CHANNEL 4 DETECT RESISTANCE Register
        56. 9.6.2.56 CHANNEL 1 DETECT CAPACITANCE Register
        57. 9.6.2.57 CHANNEL 2 DETECT CAPACITANCE Register
        58. 9.6.2.58 CHANNEL 3 DETECT CAPACITANCE Register
        59. 9.6.2.59 CHANNEL 4 DETECT CAPACITANCE Register
        60. 9.6.2.60 CHANNEL 1 ASSIGNED CLASS Register
        61. 9.6.2.61 CHANNEL 2 ASSIGNED CLASS Register
        62. 9.6.2.62 CHANNEL 3 ASSIGNED CLASS Register
        63. 9.6.2.63 CHANNEL 4 ASSIGNED CLASS Register
        64. 9.6.2.64 AUTO CLASS CONTROL Register
        65. 9.6.2.65 CHANNEL 1 AUTO CLASS POWER Register
        66. 9.6.2.66 CHANNEL 2 AUTO CLASS POWER Register
        67. 9.6.2.67 CHANNEL 3 AUTO CLASS POWER Register
        68. 9.6.2.68 CHANNEL 4 AUTO CLASS POWER Register
        69. 9.6.2.69 ALTERNATIVE FOLDBACK Register
        70. 9.6.2.70 SRAM CONTROL Register
          1. 9.6.2.70.1 SRAM START ADDRESS (LSB) Register
          2. 9.6.2.70.2 SRAM START ADDRESS (MSB) Register
  11. 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
  12. 11Power Supply Recommendations
    1. 11.1 VDD
    2. 11.2 VPWR
  13. 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
  14. 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
  15. 14Mechanical, Packaging, and Orderable Information

Package Options

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

9.6.2.17 Power Priority / 2Pair PCUT Disable Register Name

COMMAND = 15h with 1 Data Byte, R/W

Figure 9-24 Power Priority / 2P-PCUT Disable Register Format
76543210
OSS4OSS3OSS2OSS1DCUT4DCUT3DCUT2DCUT1
R/W-0R/W-0R/W-0R/W-0R/W-0R/W-0R/W-0R/W-0
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 9-22 Power Priority / 2P-PCUT Disable Register Field Descriptions
BitFieldTypeResetDescription
7–4OSS4-OSS1R/W0Power priority bits:

When the MBitPrty bit in 0x17 =0:

1 = When the OSS signal is asserted, the corresponding channel is powered off.

0 = OSS signal has no impact on the channel.

For 4-pair wired Ports, these bits control the individual Channel response. In order for both channels of a 4-pair wired port to be disabled, both channels need to be set to 1.

3–0DCUT4-DCUT1R/W02-Pair PCUT disable for each channel. Used to prevent removal of the associated channel’s power due to a 2-Pair PCUT fault, regardless of the programming status of the Timing Configuration register. Note that there is still monitoring of ILIM faults.

1: Channel’s PCUT is disabled. This means that an PCUT fault alone will not turn off this channel.

0: Channel’s PCUT is enabled. This enables channel turn off if there is PCUT fault.

Note:

If the MbitPrty bit = 1 (0x17h): The OSSn bits must be cleared to ensure proper operation. Refer to registers 0x27/28h for more information on the Multi-bit priority shutdown feature.

Note:

If DCUT = 1 for a channel, the channel will not be automatically turned off during a PCUT fault condition. However, the PCUT fault flag will still be operational, with a fault timeout equal to tOVLD.

Any change in the state of DCUTn bits will result in the resetting of the TOVLD timer for that channel.

Note:

For 4-pair wired Ports:

These bits control the individual Channel response to a 2-Pair PCUT fault.

If the NCTnn bit in 0x2D = 1 and the 2-Pair PCut is enabled, both channel will be turned off if the overload condition exceeds the tOVLD timeout.

The response to a summed 4-pair PCUT fault is configured in register 0x2Dh.

The OSSn bits are used to determine which channels are shut down in response to an external assertion of the OSS fast shutdown signal.

The turn off procedure due to OSS is similar to a channel reset or change to OFF mode, with the exception that OSS does not cancel any ongoing fault cool down timers. the table below includes the bits that will be cleared when a channel is disabled due to OSS:

Table 9-23 Channel Turn Off with OSS
RegisterBits to be reset
0x04CLSCn and DETCn
0x06DISFn and PCUTn
0x08STRTn and ILIMn
0x0A/BPCUTnn
0x0C-0FRequested Class and Detection
0x10PGn and PEn
0x14CLEn and DETEn
0x1CACn and CCnn
0x1E-212P Policing set to 0xFFh
0x24PFn
0x2A-2B4P Policing set to 0xFFh
0x2DNLMnn, NCTnn, 4PPCTnn, and DCDTnn
0x30-3FChannel Voltage and Current Measurements
0x402xFBn
0x44 - 47Detection Resistance Measurements
0x4C-4FAssigned Class and Previous Class
0x51-54Autoclass Measurement

Note:

it may take upwards of 5 ms before all of the registers are cleared following an OSS event.

Only the bits associated with the channel/port ("n") with OSS enabled will be cleared. Those bits associated with channels/ports remaining in operation will not be changed.

In the event a singular channel of a 4-pair dual signature PD is turned off due to OSS or PCUT fault, power may be reapplied to that channel by setting the PWON bit in 0x19h provided the detection and classification are still valid and the Power Allocation settings in 0x29 are sufficient based on the assigned classification of the powered channel.