SLVSGG3A May   2022  – September 2022 TPS25985

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Description (continued)
  6. 6 Pin Configuration and Functions
  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 Logic Interface
    7. 7.7 Timing Requirements
    8. 7.8 Switching Characteristics
    9. 7.9 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1  Undervoltage Protection
      2. 8.3.2  Insertion Delay
      3. 8.3.3  Overvoltage Protection
      4. 8.3.4  Inrush Current, Overcurrent, and Short-Circuit Protection
        1. 8.3.4.1 Slew rate (dVdt) and Inrush Current Control
          1. 8.3.4.1.1 Start-Up Time Out
        2. 8.3.4.2 Steady-State Overcurrent Protection (Circuit-Breaker)
        3. 8.3.4.3 Active Current Limiting During Start-Up
        4. 8.3.4.4 Short-Circuit Protection
      5. 8.3.5  Analog Load Current Monitor (IMON)
      6. 8.3.6  Mode Selection (MODE)
      7. 8.3.7  Parallel Device Synchronization (SWEN)
      8. 8.3.8  Stacking Multiple eFuses for Unlimited Scalability
        1. 8.3.8.1 Current Balancing During Start-Up
      9. 8.3.9  Analog Junction Temperature Monitor (TEMP)
      10. 8.3.10 Overtemperature Protection
      11. 8.3.11 Fault Response and Indication (FLT)
      12. 8.3.12 Power Good Indication (PG)
      13. 8.3.13 Output Discharge
      14. 8.3.14 General Purpose Comparator
      15. 8.3.15 FET Health Monitoring
      16. 8.3.16 Single Point Failure Mitigation
        1. 8.3.16.1 IMON Pin Single Point Failure
        2. 8.3.16.2 ILIM Pin Single Point Failure
        3. 8.3.16.3 IREF Pin Single Point Failure
        4. 8.3.16.4 ITIMER Pin Single Point Failure
    4. 8.4 Device Functional Modes
  9. 9 Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 Single Device, Standalone Operation
      2. 9.1.2 Multiple Devices, Parallel Connection
    2. 9.2 Typical Application: 12-V, 3.6-kW Power Path Protection in Datacenter Servers
      1. 9.2.1 Application
      2. 9.2.2 Design Requirements
      3. 9.2.3 Detailed Design Procedure
      4. 9.2.4 Application Performance Plots
    3. 9.3 Multiple eFuses, Parallel Connection with PMBus
    4. 9.4 Digital Telemetry Using External Microcontroller
    5. 9.5 What to Do and What Not to Do
  10. 10Power Supply Recommendations
    1. 10.1 Transient Protection
    2. 10.2 Output Short-Circuit Measurements
  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 Receiving Notification of Documentation Updates
    3. 12.3 Support Resources
    4. 12.4 Trademarks
    5. 12.5 Electrostatic Discharge Caution
    6. 12.6 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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

8.3.12 Power Good Indication (PG)

Power Good indication is an active high output which is asserted high to indicate when the device is in steady-state and capable of delivering maximum power.

Table 8-4 PG Indication Summary

Event or Condition

FET Status

PG Pin Status

PG Delay

Undervoltage ( VEN < VUVLO)

OFF

L

tPGD

VIN < VUVP

OFF

L

VDD < VUVP

OFF

L

Overvoltage (VIN > VOVP)

OFF

L

tPGD

Steady-state

ON

H

tPGA

Inrush

ON

L

tPGA

Transient overcurrent

ON

H

N/A

Circuit-breaker (persistent overcurrent followed by ITIMER expiry)

OFF

L (MODE = H)

H (MODE = L)

tPGD

N/A

Fast-trip

OFF

L (MODE = H)

H (MODE = L)

tPGD

N/A

ILM pin open

OFF

L (MODE = H)

H (MODE = L)

tITIMER + tPGD

N/A

ILM pin short

OFF

L (MODE = H)

H(MODE = L)

tPGD

N/A

Overtemperature

Shutdown

L (MODE = H)

H (MODE = L)

tPGD

N/A

After power up, PG is pulled low initially. The device initiates an inrush sequence in which the gate driver circuit starts charging the gate capacitance from the internal charge pump. When the FET gate voltage reaches the full overdrive indicating that the inrush sequence is complete and the device is capable of delivering full power, the PG pin is asserted HIGH after a de-glitch time (tPGA).

The PG is de-asserted if the FET is turned off at any time during normal operation. The PG de-assertion de-glitch time is tPGD.

GUID-20211230-SS0I-RKJM-LXQZ-RQVR0B9SVKQD-low.gifFigure 8-8 TPS25985x PG Timing Diagram

The PG is an open-drain pin and must be pulled up to an external supply.

When there is no supply to the device, the PG pin is expected to stay low. However, there is no active pulldown in this condition to drive this pin all the way down to 0 V. If the PG pin is pulled up to an independent supply which is present even if the device is unpowered, there can be a small voltage seen on this pin depending on the pin sink current, which is a function of the pullup supply voltage and resistor. Minimize the sink current to keep this pin voltage low enough not to be detected as a logic HIGH by associated external circuits in this condition.

When the device is used in secondary mode (MODE = GND) in conjunction with another TPS25985 device as a primary device in a parallel chain, it controls the PG assertion during start-up, but after the device reaches steady-state, it no longer has control over the PG de-assertion. Refer to the Mode Selection (MODE) for more details.