SLUSCM4B October   2017  – November 2018 TPS2372

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
  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 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 PG Power Good (Converter Enable) Pin Interface
      2. 7.3.2 CLSA and CLSB Classification, AUTCLS
      3. 7.3.3 DEN Detection and Enable
      4. 7.3.4 Internal Pass MOSFET and Inrush Delay Enable, IRSHDL_EN
      5. 7.3.5 TPH, TPL and BT PSE Type Indicators
      6. 7.3.6 AMPS_CTL, MPS_DUTY and Automatic MPS
      7. 7.3.7 VDD Supply Voltage
      8. 7.3.8 VSS
      9. 7.3.9 Exposed Thermal PAD
    4. 7.4 Device Functional Modes
      1. 7.4.1  PoE Overview
      2. 7.4.2  Threshold Voltages
      3. 7.4.3  PoE Startup Sequence
      4. 7.4.4  Detection
      5. 7.4.5  Hardware Classification
      6. 7.4.6  Autoclass
      7. 7.4.7  Inrush and Startup
      8. 7.4.8  Maintain Power Signature
      9. 7.4.9  Startup and Converter Operation
      10. 7.4.10 PD Hotswap Operation
      11. 7.4.11 Startup and Power Management, PG and TPH, TPL, BT
      12. 7.4.12 Using DEN to Disable PoE
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Requirements
        1. 8.2.2.1  Input Bridges and Schottky Diodes
        2. 8.2.2.2  Protection, D1
        3. 8.2.2.3  Capacitor, C1
        4. 8.2.2.4  Detection Resistor, RDEN
        5. 8.2.2.5  Classification Resistors, RCLSA and RCLSB
        6. 8.2.2.6  Opto-isolators for TPH, TPL and BT
        7. 8.2.2.7  Automatic MPS and MPS Duty Cycle, RMPS and RMPS_DUTY
        8. 8.2.2.8  Internal Voltage Reference, RREF
        9. 8.2.2.9  Autoclass
        10. 8.2.2.10 Inrush Delay
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
    3. 10.3 EMI Containment
    4. 10.4 Thermal Considerations and OTSD
    5. 10.5 ESD
  11. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Related Links
      2. 11.1.2 Related Documentation
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Community Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • RGW|20
Thermal pad, mechanical data (Package|Pins)
Orderable Information

7.3.5 TPH, TPL and BT PSE Type Indicators

The state of BT, TPH and TPL is used to provide information relative to the PSE Type (1-2 or 3-4) and its allocated power. Table 2 lists the encoding corresponding to various combinations of PSE Type, PD Class and allocated power. Table 3 also corresponds to cases where the PSE allocated power is lower than what the PD is requesting. The allocated power is determined by the number of classification cycles having been received. During startup, the TPH, TPL and BT outputs are enabled typically 24 ms after PG went from low to open, to allow the power supply to reach a stable state first. These 3 outputs will return to a high-impedance state if the part enters thermal shutdown, or if VDD-to-VSS voltage falls below ~32 V. Note that in all these cases, as long as VDD-to-VSS voltage remains above the mark reset threshold, the internal logic state of these 3 signals is remembered such that these outputs will be activated accordingly after the startup has completed. This circuit resets when the VDD-to-VSS voltage drops below the mark reset threshold. The TPH, TPL and BT pins can be left unconnected if not used.

Table 2. TPH, TPL, BT and Allocated Power Truth Table

PSE Type PD Class NUMBER OF CLASS CYCLES PSE ALLOCATED POWER AT PD (W) TPH TPL BT(1)
1-2 0 1 12.95 HIGH HIGH HIGH
1-2 1 1 3.84 HIGH HIGH HIGH
1-2 2 1 6.49 HIGH HIGH HIGH
1-2 3 1 12.95 HIGH HIGH HIGH
2 4 2 25.5 HIGH LOW HIGH
3-4 0 1 12.95 HIGH HIGH LOW
3-4 1 1 3.84 HIGH HIGH LOW
3-4 2 1 6.49 HIGH HIGH LOW
3-4 3 1 12.95 HIGH HIGH LOW
3-4 4 2-3 25.5 HIGH LOW LOW
3-4 5 4 40 LOW HIGH LOW
3-4 6 4 51 LOW HIGH LOW
4 7 5 62 LOW LOW LOW
4 8 5 71 LOW LOW LOW
(1) The BT output is not required to indicate how much power is allocated to the PD by a IEEE802.3bt compliant PSE. Additional information may be provided depending on the application described in the Application Detailed Design Requirements section Opto-isolators for TPH, TPL and BT

Table 3. Power Demotion Cases

PSE Type PD Class NUMBER OF CLASS CYCLES PSE ALLOCATED POWER AT PD (W) TPH TPL BT
3-4 4-8 1 12.95 HIGH HIGH LOW
3-4 5-8 2,3 25.5 HIGH LOW LOW
3-4 7-8 4 51 LOW HIGH LOW