SLUSDC7A March   2020  – November 2020 BQ25306


  1. Features
  2. Applications
  3. Description
  4. Revision History
  5. Description (continued)
  6. Device Comparison Table
  7. Pin Configuration and Functions
  8. Specifications
    1. 8.1 Absolute Maximum Ratings
    2. 8.2 ESD Ratings
    3. 8.3 Recommended Operating Conditions
    4. 8.4 Thermal Information
    5. 8.5 Electrical Characteristics
    6. 8.6 Timing Requirements
    7. 8.7 Typical Characteristics
  9. Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1 Device Power Up
        1. Power-On-Reset (POR)
        2. REGN Regulator Power Up
        3. Charger Power Up
        4. Charger Enable and Disable by EN Pin
        5. Device Unplugged from Input Source
      2. 9.3.2 Battery Charging Management
        1. Battery Charging Profile
        2. Precharge
        3. Charging Termination
        4. Battery Recharge
        5. Charging Safety Timer
        6. Thermistor Temperature Monitoring
      3. 9.3.3 Charging Status Indicator (STAT)
      4. 9.3.4 Protections
        1. Voltage and Current Monitoring
          1. Input Over-Voltage Protection
          2. Input Voltage Dynamic Power Management (VINDPM)
          3. Input Current Limit
          4. Cycle-by-Cycle Current Limit
        2. Thermal Regulation and Thermal Shutdown
        3. Battery Protection
          1. Battery Over-Voltage Protection (VBAT_OVP)
          2. Battery Short Circuit Protection
        4. ICHG Pin Open and Short Protection
    4. 9.4 Device Functional Modes
      1. 9.4.1 Disable Mode, HiZ Mode, Sleep Mode, Charge Mode, Termination Mode, and Fault Mode
  10. 10Application and Implementation
    1. 10.1 Application Information
    2. 10.2 Typical Applications
      1. 10.2.1 Typical Application
        1. Design Requirements
        2. Detailed Design Procedure
          1. Charge Voltage Settings
          2. Charge Current Setting
          3. Inductor Selection
          4. Input Capacitor
          5. Output Capacitor
        3. Application Curves
      2. 10.2.2 Typical Application with External Power Path
        1. Design Requirements
      3. 10.2.3 Typical Application with MCU Programmable Charge Current
        1. Design Requirements
  11. 11Power Supply Recommendations
  12. 12Layout
    1. 12.1 Layout Guidelines
    2. 12.2 Layout Example
  13. 13Device and Documentation Support
    1. 13.1 Device Support
      1. 13.1.1 Third-Party Products Disclaimer
    2. 13.2 Documentation Support
      1. 13.2.1 Related Documentation
    3. 13.3 Receiving Notification of Documentation Updates
    4. 13.4 Support Resources
    5. 13.5 Trademarks
    6. 13.6 Electrostatic Discharge Caution
    7. 13.7 Glossary
  14. 14Mechanical, Packaging, and Orderable Information

Package Options

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

Description (continued)

The BQ25306 supports a 4.1-V to 17-V input to charge either single cell batteries or dual batteries in series with charge voltage from 3.4 V to 9.0 V programmable by resistor divider. The BQ25306 provides up to 3-A continuous charge current to a single cell (1S) battery or dual cell batteries in series (2S). The device features fast charging for portable devices. Its input voltage regulation delivers maximum charging power to the battery from 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 BQ25306 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 BQ25306 charge voltage and charge current are set by external resistors. The BQ25306 charge voltage is programmed by an external resister divider and it charges the battery in three phases: 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 battery voltage feedback pin FB or feedback resistors accidently open or short. 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 BQ25306 is available in a 3 mm x 3 mm thin WQFN package.