SLUSFM5 March   2025 BQ76907-Q1

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison Table
  6. 5 Pin Configuration and Functions
  7. 6 Specifications
    1. 6.1  Absolute Maximum Ratings
    2. 6.2  ESD Ratings
    3. 6.3  Recommended Operating Conditions
    4. 6.4  Thermal Information BQ76907-Q1
    5. 6.5  Supply Current
    6. 6.6  Digital I/O
    7. 6.7  REGOUT LDO
    8. 6.8  Voltage References
    9. 6.9  Coulomb Counter
    10. 6.10 Coulomb Counter Digital Filter
    11. 6.11 Current Wake Detector
    12. 6.12 Analog-to-Digital Converter
    13. 6.13 Cell Voltage Measurement Accuracy
    14. 6.14 Cell Balancing
    15. 6.15 Internal Temperature Sensor
    16. 6.16 Thermistor Measurement
    17. 6.17 Hardware Overtemperature Detector
    18. 6.18 Internal Oscillator
    19. 6.19 Charge and Discharge FET Drivers
    20. 6.20 Comparator-Based Protection Subsystem
    21. 6.21 Timing Requirements - I2C Interface, 100kHz Mode
    22. 6.22 Timing Requirements - I2C Interface, 400kHz Mode
    23. 6.23 Timing Diagram
    24. 6.24 Typical Characteristics
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Device Configuration
      1. 7.3.1 Commands and Subcommands
      2. 7.3.2 Configuration Using OTP or Registers
      3. 7.3.3 Device Security
    4. 7.4 Device Hardware Features
      1. 7.4.1  Voltage ADC
      2. 7.4.2  Coulomb Counter and Digital Filters
      3. 7.4.3  Protection FET Drivers
      4. 7.4.4  Voltage References
      5. 7.4.5  Multiplexer
      6. 7.4.6  LDOs
      7. 7.4.7  Standalone Versus Host Interface
      8. 7.4.8  ALERT Pin Operation
      9. 7.4.9  Low Frequency Oscillator
      10. 7.4.10 I2C Serial Communications Interface
    5. 7.5 Measurement Subsystem
      1. 7.5.1 Voltage Measurement
        1. 7.5.1.1 Voltage ADC Scheduling
        2. 7.5.1.2 Unused VC Pins
        3. 7.5.1.3 General Purpose ADCIN Functionality
      2. 7.5.2 Current Measurement and Charge Integration
      3. 7.5.3 Internal Temperature Measurement
      4. 7.5.4 Thermistor Temperature Measurement
      5. 7.5.5 Factory Trim and Calibration
    6. 7.6 Protection Subsystem
      1. 7.6.1 Protections Overview
      2. 7.6.2 Primary Protections
      3. 7.6.3 CHG Detector
      4. 7.6.4 Cell Open-Wire Protection
      5. 7.6.5 Diagnostic Checks
    7. 7.7 Cell Balancing
    8. 7.8 Device Operational Modes
      1. 7.8.1 Overview of Operational Modes
      2. 7.8.2 NORMAL Mode
      3. 7.8.3 SLEEP Mode
      4. 7.8.4 DEEPSLEEP Mode
      5. 7.8.5 SHUTDOWN Mode
      6. 7.8.6 CONFIG_UPDATE Mode
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
      3. 8.2.3 Application Performance Plot
      4. 8.2.4 Random Cell Connection Support
      5. 8.2.5 Startup Timing
      6. 8.2.6 FET Driver Turn-Off
      7. 8.2.7 Usage of Unused Pins
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Documentation Support
      1. 9.1.1 Related Documentation
    2. 9.2 Receiving Notification of Documentation Updates
    3. 9.3 Support Resources
    4. 9.4 Trademarks
    5. 9.5 Electrostatic Discharge Caution
    6. 9.6 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information

7.4.6 LDOs

The BQ76907-Q1 contains an integrated 1.8V LDO (REG18) that provides a regulated 1.8V supply voltage for the device's internal circuitry and digital logic. The supply current for this LDO is drawn from the BAT pin.

The device also integrates a programmable LDO (REGOUT) for external circuitry, such as a host processor or external transceiver circuitry. The REGOUT LDO's input is the REGSRC pin, which is generally expected to be connected to the top-of-the-stack, or the REGSRC voltage can be generated by a separate DC/DC converter in the system. The REGOUT LDO can provide an output current of up to 20mA if thermal conditions permit.

The REGOUT LDO can be programmed to either remain disabled or power up automatically whenever the device exits SHUTDOWN mode, depending on OTP configuration. The LDO output voltage can be programmed to 1.8V, 2.5V, 3.0V, 3.3V, or 5.0V by modifying configuration settings. When the REGOUT LDO is disabled and the device is in NORMAL, SLEEP, or DEEPSLEEP modes, the output is pulled to VSS with an internal resistance of approximately 2.5kΩ. If the LDO is configured based on OTP settings to be powered, then at each later power-up the device autonomously loads the OTP settings and enables the LDO as configured, without requiring communications first.

The BQ76907-Q1 is designed to operate properly with a die temperature of up to 125°C, therefore the system design must avoid drawing excessive current from the REGOUT LDO if this results in the die temperature exceeding this level. For example, with a stack voltage of 31.5V, and REGOUT programmed to an output voltage of 2.5V, the device dissipates approximately 580mW when supplying 20mA of load current. The package thermal impedance can be used to then calculate the resulting die temperature based on the maximum ambient temperature expected. If this exceeds the device's specified temperature range, the load current must be limited in the system.

The BQ76907-Q1 includes a die temperature monitor which detects if the die temperature exceeds approximately 120°C. If this occurs, the REGOUT LDO is disabled, and depending on configuration setting, the device also enters SHUTDOWN mode. If the REGOUT LDO is disabled due to overtemperature (but the device is not shut down) and the die temperature reduces below the threshold, the REGOUT LDO automatically powers on again.