SLUSFD7 April   2024 BQ25308

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Description (continued)
  6. 5 Device Comparison Table
  7. 6 Pin Configuration and Functions
  8. 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
  9. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Device Power Up
        1. 8.3.1.1 Power-On-Reset (POR)
        2. 8.3.1.2 REGN Regulator Power Up
        3. 8.3.1.3 Charger Power Up
        4. 8.3.1.4 Charger Enable and Disable by EN Pin
        5. 8.3.1.5 Device Unplugged From Input Source
      2. 8.3.2 Battery Charging Management
        1. 8.3.2.1 Battery Charging Profile
        2. 8.3.2.2 Battery Charging Profile for LiFePO4
        3. 8.3.2.3 Precharge
        4. 8.3.2.4 Charging Termination
        5. 8.3.2.5 Battery Recharge
        6. 8.3.2.6 Charging Safety Timer
        7. 8.3.2.7 Thermistor Temperature Monitoring
      3. 8.3.3 Charging Status Indicator (STAT)
      4. 8.3.4 Protections
        1. 8.3.4.1 Voltage and Current Monitoring
          1. 8.3.4.1.1 Input Over-Voltage Protection
          2. 8.3.4.1.2 Input Voltage Dynamic Power Management (VINDPM)
          3. 8.3.4.1.3 Input Current Limit
          4. 8.3.4.1.4 Cycle-by-Cycle Current Limit
        2. 8.3.4.2 Thermal Regulation and Thermal Shutdown
        3. 8.3.4.3 Battery Protection
          1. 8.3.4.3.1 Battery Over-Voltage Protection (VBAT_OVP)
          2. 8.3.4.3.2 Dead Battery Charge Inhibit
        4. 8.3.4.4 ICHG Pin Open and Short Protection
    4. 8.4 Device Functional Modes
      1. 8.4.1 Disable Mode, HiZ Mode, Sleep Mode, Charge Mode, Termination Mode, and Fault Mode
  10. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Applications
      1. 9.2.1 Typical Application
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
          1. 9.2.1.2.1 Charge Voltage Settings
          2. 9.2.1.2.2 Charge Current Setting
          3. 9.2.1.2.3 Inductor Selection
          4. 9.2.1.2.4 Input Capacitor
          5. 9.2.1.2.5 Output Capacitor
        3. 9.2.1.3 Application Curves
      2. 9.2.2 Typical Application with External Power Path
        1. 9.2.2.1 Design Requirements
        2. 9.2.2.2 Detailed Design Procedure
        3. 9.2.2.3 Application Curves
  11. 10Power Supply Recommendations
  12. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  13. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 Third-Party Products Disclaimer
    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
  14. 13Revision History
  15. 14Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • RTE|16
Thermal pad, mechanical data (Package|Pins)
Orderable Information
9.2.1.2.3 Inductor Selection

The 1.2-MHz switching frequency allows the use of small inductor and capacitor values. The inductance value is selected based on the maximum input voltage VVBUS_MAX in the application. A 1-µH inductor is recommended if VVBUS_MAX < 6.2V and a 2.2-µH inductor is recommended if VVBUS_MAX > 6.2V. Inductor saturation current ISAT should be higher than the charging current ICHG plus half the ripple current IRIPPLE:

Equation 3. ISAT ≥ ICHG + (1/2) IRIPPLE

The inductor ripple current IRIPPLE depends on the input voltage (VVBUS), the duty cycle (D = VBAT/VVBUS), the switching frequency (fS), and the inductance (L).

Equation 4. GUID-58D6EC74-40EE-4838-8D55-16FFA87707B6-low.gif

The maximum inductor ripple current occurs when the duty cycle (D) is 0.5 or approximately 0.5.