SLDS206E November   2014  – February 2021 TPS65218

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1. 3.1 Simplified Schematic
  4. 4 Revision History
  5. 5 Pin Configuration and 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 Timing Requirements
    7. 6.7 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 Wake-Up and Power-Up and Power-Down Sequencing
        1. 7.3.1.1  Power-Up Sequencing
        2. 7.3.1.2  Power-Down Sequencing
        3. 7.3.1.3  Strobe 1 and Strobe 2
        4. 7.3.1.4  Supply Voltage Supervisor and Power-Good (PGOOD)
        5. 7.3.1.5  Backup Supply Power-Good (PGOOD_BU)
        6. 7.3.1.6  Internal LDO (INT_LDO)
        7. 7.3.1.7  Current Limited Load Switches
          1. 7.3.1.7.1 Load Switch 1 (LS1)
          2. 7.3.1.7.2 Load Switch 2 (LS2)
          3. 7.3.1.7.3 Load Switch 3 (LS3)
        8. 7.3.1.8  LDO1
        9. 7.3.1.9  Coin Cell Battery Voltage Acquisition
        10. 7.3.1.10 UVLO
        11. 7.3.1.11 Power-Fail Comparator
        12. 7.3.1.12 Battery-Backup Supply Power-Path
        13. 7.3.1.13 DCDC3 and DCDC4 Power-Up Default Selection
        14. 7.3.1.14 I/O Configuration
          1. 7.3.1.14.1 Configuring GPO2 as Open-Drain Output
          2. 7.3.1.14.2 Using GPIO3 as Reset Signal to DCDC1 and DCDC2
        15. 7.3.1.15 Push Button Input (PB)
          1. 7.3.1.15.1 Signaling PB-Low Event on the nWAKEUP Pin
          2. 7.3.1.15.2 Push Button Reset
        16. 7.3.1.16 AC_DET Input (AC_DET)
        17. 7.3.1.17 Interrupt Pin (INT)
        18. 7.3.1.18 I2C Bus Operation
    4. 7.4 Device Functional Modes
      1. 7.4.1 Modes of Operation
      2. 7.4.2 OFF
      3. 7.4.3 ACTIVE
      4. 7.4.4 SUSPEND
      5. 7.4.5 RESET
    5. 7.5 Register Maps
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Applications Without Backup Battery
      2. 8.1.2 Applications Without Battery Backup Supplies
    2. 8.2 Typical Application
      1. 8.2.1 Detailed Design Procedure
        1. 8.2.1.1 Output Filter Design
        2. 8.2.1.2 Inductor Selection for Buck Converters
        3. 8.2.1.3 Output Capacitor Selection
      2. 8.2.2 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Related Documentation
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Support Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

7.3.1.6 Internal LDO (INT_LDO)

The internal LDO provides a regulated voltage to the internal digital core and analog circuitry. The internal LDO has a nominal output voltage of 2.5 V and can support up to 10 mA of external load.

When system power fails, the UVLO comparator triggers the power-down sequence. If system power drops below 2.5 V, the digital core is reset and all remaining power rails are shut down instantaneously and are pulled low to ground by their internal discharge circuitry (DCDC1-4 and LDO1).

The internal LDO reverse blocks to prevent the discharging of the output capacitor (CINT_LDO) on the INT_LDO pin. The remaining charge on the INT_LDO output capacitor provides a supply for the power rail discharge circuitry to ensure the outputs are discharged to ground even if the system supply has failed. The amount of hold-up time specified in Section 6.5 is a function of the output capacitor value (CINT_LDO) and the amount of external load on the INT_LDO pin, if any. The design allows for enough hold-up time to sufficiently discharge DCDC1-4, and LDO1 to ensure proper processor power-down sequencing. The amount of hold-up time is a function of the output capacitor value, which should not exceed 22 μF and the amount of external load, if any.

GUID-EB90B8C1-5404-4950-B3B0-92F993792202-low.gifFigure 7-9 Internal LDO and UVLO Sensing