SLVSIB0 December   2025 UCD91320

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 ESD Ratings
    3. 5.3 Recommended Operating Conditions
    4. 5.4 Thermal Information
    5. 5.5 Electrical Characteristics
    6. 5.6 Linearity Parameters
    7. 5.7 POR and BOR
    8. 5.8 Low Frequency Crystal/Clock
    9. 5.9 Flash Memory Characteristics
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Feature Description
      1. 6.2.1 TI Sequencer Studio Software
      2. 6.2.2 PMBUS Interface
      3. 6.2.3 PMBUS Security
    3. 6.3 Device Functional Modes
      1. 6.3.1 Black Box Fault Logging
      2. 6.3.2 PMBus Address Selection
      3. 6.3.3 Brownout
    4.     Failure Analysis and Returns
  8. 7 Application and Implementation
    1. 7.1 Application Information
    2. 7.2 Typical Application
      1. 7.2.1 Design Requirements
      2. 7.2.2 Detailed Design Procedure
      3. 7.2.3 Application Curves
    3. 7.3 Power Supply Recommendations
    4. 7.4 Layout
      1. 7.4.1 Layout Guidelines
  9. 8 Device and Documentation Support
    1. 8.1 Receiving Notification of Documentation Updates
    2. 8.2 Support Resources
    3. 8.3 Trademarks
    4. 8.4 Electrostatic Discharge Caution
    5. 8.5 Glossary
  10. 9 Revision History
  11. 10Mechanical, Packaging, and Orderable Information

6.3.1 Black Box Fault Logging

The first fault in a system failure event may be critical to diagnose the root cause. When UCD91320 detects an initial fault, the device records and saves the status of each rail in a special area (Black Box) of the NVM reserved for this function. The device does not save the subsequent faults and monitoring statuses into the Black Box Fault Log, but instead records them into the standard fault log. The last fault log when the BOR voltage is crossed is also saved to the black box fault log. The Black Box Fault Log must be cleared via a PMBus command before another black box fault log can be collected.