ZHCSM97A November   2020  – August 2021 TPS6521845

PRODUCTION DATA  

  1. 1 特性
  2. 2 应用
  3. 3 说明
    1.     4
  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 Battery Backup Supplies
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Output Filter Design
        2. 8.2.2.2 Inductor Selection for Buck Converters
        3. 8.2.2.3 Output Capacitor Selection
      3. 8.2.3 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 支持资源
    4. 11.4 Trademarks
    5. 11.5 静电放电警告
    6. 11.6 术语表
  12. 12Mechanical, Packaging, and Orderable Information

封装选项

机械数据 (封装 | 引脚)
散热焊盘机械数据 (封装 | 引脚)
订购信息

8.2.2.3 Output Capacitor Selection

The hysteretic PWM control scheme of the TPS6521845 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 8-2 lists the recommended capacitors.

Table 8-3 List of Recommended Capacitors
PART NUMBER VALUE SIZE (mm) [L × W × H] MANUFACTURER
CAPACITORS FOR VOLTAGES UP TO 5.5 V(1)
GRM188R60J105K 1 µF 1608 / 0603 (1.6 × 0.8 × 0.8) Murata
GRM21BR60J475K 4.7 µF 2012 / 0805 (2.0 × 1.25 × 1.25) Murata
GRM31MR60J106K 10 µF 3216 / 1206 (3.2 × 1.6 × 1.6) Murata
GRM31CR60J226K 22 µF 3216 / 1206 (3.2 × 1.6 × 1.6) Murata
CAPACITORS FOR VOLTAGES UP TO 3.3 V(1)
GRM21BR60J106K 10 µF 2012 / 0805 (2.0 × 1.25 × 1.25) Murata
(1) The DC bias effect of ceramic capacitors must be considered when selecting a capacitor.