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

9.2.2.3 Output Capacitor Selection

The hysteretic PWM control scheme of the TPS6521815 switching converters allows the use of tiny ceramic capacitors. Ceramic capacitors with low ESR values have the lowest output voltage ripple and are recommended. The output capacitor requires either an X7R or X5R dielectric.

At light load currents the converter operates in power save mode, and the output voltage ripple is dependent on the output capacitor value and the PFM peak inductor current. Higher output capacitor values minimize the voltage ripple in PFM Mode and tighten DC output accuracy in PFM mode.

The two battery backup converters (DCDC5 and DCDC6) always operate in PFM mode. For these converters, a capacitor of at least 20 µF is recommended on the output to help minimize voltage ripple.

The buck-boost converter requires additional output capacitance to help maintain converter stability during high load conditions. At least 40 µF of output capacitance is recommended and an additional 100-nF capacitor can be added to further filter output ripple at higher frequencies.

Table 9-2 lists the recommended capacitors.

Table 9-3 List of Recommended Capacitors
PART NUMBERVALUESIZE (mm) [L × W × H]MANUFACTURER
CAPACITORS FOR VOLTAGES UP TO 5.5 V(1)
GRM188R60J105K1 µF1608 / 0603 (1.6 × 0.8 × 0.8)Murata
GRM21BR60J475K4.7 µF2012 / 0805 (2.0 × 1.25 × 1.25)Murata
GRM31MR60J106K10 µF3216 / 1206 (3.2 × 1.6 × 1.6)Murata
GRM31CR60J226K22 µF3216 / 1206 (3.2 × 1.6 × 1.6)Murata
CAPACITORS FOR VOLTAGES UP TO 3.3 V(1)
GRM21BR60J106K10 µF2012 / 0805 (2.0 × 1.25 × 1.25)Murata
GRM31CR60J476M47 µF3216 / 1206 (3.2 × 1.6 × 1.6)Murata
(1) The DC bias effect of ceramic capacitors must be considered when selecting a capacitor.