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

4 Description (continued)

The BQ25308 supports a 4.1V to 17V input to charge single cell batteries. The BQ25308 provides up to 3A continuous charge current to a single cell 1S battery. The device features fast charging for portable devices. Its input voltage regulation delivers maximum charging power to the battery from the input source. The solution is highly integrated with an input reverse-blocking FET (RBFET, Q1), high-side switching FET (HSFET, Q2), and low-side switching FET (LSFET, Q3). The device also provides a safety feature that completely inhibits charging of a dead battery.

The BQ25308 features lossless integrated current sensing to reduce power loss and BOM cost with minimized component count. It also integrates a bootstrap diode for the high-side gate drive and battery temperature monitor to simplify system design. The device initiates and completes a charging cycle without host control. The BQ25308 charge voltage and charge current are set by external resistors. The BQ25308 detects the charge voltage setting at startup and charges the battery in four phases: battery short, pre-conditioning, constant current, and constant voltage. At the end of the charging cycle, the charger automatically terminates if the charge current is below the termination current threshold and the battery voltage is above the recharge threshold. When the battery voltage falls below the recharge threshold, the charger will automatically start another charging cycle. The charger provides various safety features for battery charging and system operations, including battery temperature monitoring based on negative temperature coefficient (NTC) thermistor, charge safety timer, input over-voltage and over-current protections, as well as battery over-voltage protection. Pin open and short protection is also built in to protect against the charge current setting pin ICHG accidently open or short to GND. The thermal regulation regulates charge current to limit die temperature during high power operation or high ambient temperature conditions.

The STAT pin output reports charging status and fault conditions. When the input voltage is removed, the device automatically enters HiZ mode with very low leakage current from battery to the charger device. The BQ25308 is available in a 3mm x 3mm thin WQFN package.