SLUSFA4B June   2023  – February 2024 BQ25628E

PRODUCTION DATA  

  1.   1
  2. Features
  3. Applications
  4. Description
  5. Description (continued)
  6. Device Comparison
  7. Pin Configuration and Functions
  8. 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. Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Power-On-Reset (POR)
      2. 8.3.2 Device Power Up from Battery
      3. 8.3.3 Device Power Up from Input Source
        1. 8.3.3.1 REGN LDO Power Up
        2. 8.3.3.2 Poor Source Qualification
        3. 8.3.3.3 ILIM Pin
        4. 8.3.3.4 Input Voltage Limit Threshold Setting (VINDPM Threshold)
        5. 8.3.3.5 Converter Power-Up
      4. 8.3.4 Power Path Management
        1. 8.3.4.1 Narrow VDC Architecture
        2. 8.3.4.2 Dynamic Power Management
        3. 8.3.4.3 High Impedance Mode
      5. 8.3.5 Battery Charging Management
        1. 8.3.5.1 Autonomous Charging Cycle
        2. 8.3.5.2 Battery Charging Profile
        3. 8.3.5.3 Charging Termination
        4. 8.3.5.4 Thermistor Qualification
          1. 8.3.5.4.1 Advanced Temperature Profile in Charge Mode
          2. 8.3.5.4.2 TS Pin Thermistor Configuration
          3. 8.3.5.4.3 JEITA Charge Rate Scaling
          4. 8.3.5.4.4 TS_BIAS Pin
        5. 8.3.5.5 Charging Safety Timers
      6. 8.3.6 Integrated 12-Bit ADC for Monitoring
      7. 8.3.7 Status Outputs ( PG, STAT, INT)
        1. 8.3.7.1 PG Pin Power Good Indicator
        2. 8.3.7.2 Interrupts and Status, Flag and Mask Bits
        3. 8.3.7.3 Charging Status Indicator (STAT)
        4. 8.3.7.4 Interrupt to Host ( INT)
      8. 8.3.8 BATFET Control
        1. 8.3.8.1 Shutdown Mode
        2. 8.3.8.2 Ship Mode
        3. 8.3.8.3 System Power Reset
      9. 8.3.9 Protections
        1. 8.3.9.1 Voltage and Current Monitoring in Battery Only and HIZ Modes
          1. 8.3.9.1.1 Battery Undervoltage Lockout
          2. 8.3.9.1.2 Battery Overcurrent Protection
        2. 8.3.9.2 Voltage and Current Monitoring in Buck Mode
          1. 8.3.9.2.1 Input Overvoltage
          2. 8.3.9.2.2 System Overvoltage Protection (SYSOVP)
          3. 8.3.9.2.3 Forward Converter Cycle-by-Cycle Current Limit
          4. 8.3.9.2.4 System Short
          5. 8.3.9.2.5 Battery Overvoltage Protection (BATOVP)
          6. 8.3.9.2.6 Sleep and Poor Source Comparators
        3. 8.3.9.3 Thermal Regulation and Thermal Shutdown
          1. 8.3.9.3.1 Thermal Protection in Buck Mode
          2. 8.3.9.3.2 Thermal Protection in Battery-Only Mode
    4. 8.4 Device Functional Modes
      1. 8.4.1 Host Mode and Default Mode
      2. 8.4.2 Register Bit Reset
    5. 8.5 Programming
      1. 8.5.1 Serial Interface
        1. 8.5.1.1 Data Validity
        2. 8.5.1.2 START and STOP Conditions
        3. 8.5.1.3 Byte Format
        4. 8.5.1.4 Acknowledge (ACK) and Not Acknowledge (NACK)
        5. 8.5.1.5 Target Address and Data Direction Bit
        6. 8.5.1.6 Single Write and Read
        7. 8.5.1.7 Multi-Write and Multi-Read
    6. 8.6 Register Maps
      1. 8.6.1 Register Programming
      2. 8.6.2 BQ25628E Registers
  10. Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Inductor Selection
        2. 9.2.2.2 Input Capacitor
        3. 9.2.2.3 Output Capacitor
      3. 9.2.3 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 Documentation Support
      1. 12.2.1 Related Documentation
    3. 12.3 Receiving Notification of Documentation Updates
    4. 12.4 Support Resources
    5. 12.5 Trademarks
    6. 12.6 Electrostatic Discharge Caution
    7. 12.7 Glossary
  14. 13Revision History
  15. 14Mechanical, Packaging, and Orderable Information

Package Options

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

Serial Interface

The BQ25628E uses an I2C compatible interface for flexible charging parameter programming and instantaneous device status reporting. I2C is a bi-directional 2-wire serial interface. Only two open-drain bus lines are required: a serial data line (SDA), and a serial clock line (SCL).

The device has 7-bit I2C address 0x6A, receiving control inputs from a host device such as a micro-controller or digital signal processor through register addresses 0x02 – 0x38. The host device initiates all transfers and the charger responds. Register reads outside of these addresses return 0xFF. When the bus is free, both SDA and SCL lines are HIGH.

The I2C interface supports standard mode (up to 100 kbits/s), fast mode (up to 400 kbits/s) and fast mode plus (up to 1 Mbits/s.) These lines are pulled up to a reference voltage via pull-up resistor. The device I2C detection thresholds support a communication reference voltage from 1.2 V to 5 V.

Due to the ultra low IQ when the device operates in low power mode, it is necessary ensure a minimum of 128μs between a START command and any subsequent START command on the I2C bus. The recommended minimum tbuf (bus free time between a STOP and START condition) depends on the I2C mode:

  • Standard mode (100 kbits/s):
    • No additional requirements
  • Fast mode (400 kbits/s):
    • Increase I2C tbuf to at least 80 μs
    • If using repeated start commands, ensure I2C tsu:STA is at least 80 μs
  • Fast mode plus (1 Mbits/s):
    • Increase I2C tbuf to at least 120 μs
    • If using repeated start commands, ensure I2C tsu:STA is at least 120 μs

These recommendations assume a successful I2C transaction. It is also necessary to ensure a minimum 128μs time between two START commands in the case of a NACK.