SLDS261A November   2019  – February 2021 TPS6521815

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1. 3.1 Simplified Schematic
  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 Timing Requirements
    7. 7.7 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 Wake-Up and Power-Up and Power-Down Sequencing
        1. 8.3.1.1  Power-Up Sequencing
        2. 8.3.1.2  Power-Down Sequencing
        3. 8.3.1.3  Strobe 1 and Strobe 2
        4. 8.3.1.4  Supply Voltage Supervisor and Power-Good (PGOOD)
        5. 8.3.1.5  Backup Supply Power-Good (PGOOD_BU)
        6. 8.3.1.6  Internal LDO (INT_LDO)
        7. 8.3.1.7  Current Limited Load Switches
          1. 8.3.1.7.1 Load Switch 1 (LS1)
          2. 8.3.1.7.2 Load Switch 2 (LS2)
          3. 8.3.1.7.3 Load Switch 3 (LS3)
        8. 8.3.1.8  LDO1
        9. 8.3.1.9  Coin Cell Battery Voltage Acquisition
        10. 8.3.1.10 UVLO
        11. 8.3.1.11 Power-Fail Comparator
        12. 8.3.1.12 Battery-Backup Supply Power-Path
        13. 8.3.1.13 DCDC3 and DCDC4 Power-Up Default Selection
        14. 8.3.1.14 I/O Configuration
          1. 8.3.1.14.1 Configuring GPO2 as Open-Drain Output
          2. 8.3.1.14.2 Using GPIO3 as Reset Signal to DCDC1 and DCDC2
        15. 8.3.1.15 Push Button Input (PB)
          1. 8.3.1.15.1 Signaling PB-Low Event on the nWAKEUP Pin
          2. 8.3.1.15.2 Push Button Reset
        16. 8.3.1.16 AC_DET Input (AC_DET)
        17. 8.3.1.17 Interrupt Pin (INT)
        18. 8.3.1.18 I2C Bus Operation
    4. 8.4 Device Functional Modes
      1. 8.4.1 Modes of Operation
      2. 8.4.2 OFF
      3. 8.4.3 ACTIVE
      4. 8.4.4 SUSPEND
      5. 8.4.5 RESET
    5. 8.5 Programming
      1. 8.5.1 Programming Power-Up Default Values
    6. 8.6 Register Maps
  9. 9 Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 Applications Without Backup Battery
      2. 9.1.2 Applications Without Battery Backup Supplies
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Output Filter Design
        2. 9.2.2.2 Inductor Selection for Buck Converters
        3. 9.2.2.3 Output Capacitor Selection
      3. 9.2.3 Application Curves
  10. 10Power Supply Recommendations
  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

8.3.1.11 Power-Fail Comparator

The power-fail comparator notifies the system host if the system supply voltage drops and the system is at risk of shutting down. The comparator has an internal 800-mV threshold and the trip-point is adjusted by an external resistor divider.

By default, the power-fail comparator has no impact on any of the power rails or load switches. Load switches are configured individually, to be disabled when the PFI comparator trips to shed system load and extend hold-up time as described in Section 8.3.1.7. The power-fail comparator also triggers the power-down sequencer, such that all or selective rails power-down when the system voltage fails. To tie the power-fail comparator into the power-down sequence, the OFFnPFO bit in the CONTROL register must be set to 1.

The power-fail comparator cannot be monitored by software, such that no interrupt or status bit is associated to this function.

GUID-F15CB200-4F30-4F4F-9385-0F750F191C62-low.gif Figure 8-16 Power-Fail Comparator Simplified Circuit and Timing Diagram