SLUSE96 November   2023 BQ76907

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
    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 Balancing
    14. 6.14 Internal Temperature Sensor
    15. 6.15 Thermistor Measurement
    16. 6.16 Hardware Overtemperature Detector
    17. 6.17 Internal Oscillator
    18. 6.18 Charge and Discharge FET Drivers
    19. 6.19 Comparator-Based Protection Subsystem
    20. 6.20 Timing Requirements - I2C Interface, 100kHz Mode
    21. 6.21 Timing Requirements - I2C Interface, 400kHz Mode
    22. 6.22 Timing Diagram
    23. 6.23 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
  10. 9 Power Supply Recommendations
  11. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  12. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Related Documentation
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Support Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  13. 12Revision History
  14. 13Introduction to Mechanical, Packaging, and Orderable Information

Package Options

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

7.4.6 LDOs

The BQ76907 contains an integrated 1.8 V LDO (REG18) that provides a regulated 1.8-V 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 takes its input from the REGSRC pin, which is generally expected to be connected to the top-of-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 20 mA 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 1.8 V, 2.5 V, 3.0 V, 3.3 V, or 5.0 V by modifying configuration settings. When the REGOUT LDO is disabled and the device is in NORMAL, SLEEP, or DEEPSLEEP modes, its output is pulled to VSS with an internal resistance of approximately 2.5-kΩ. If the LDO is configured based on OTP settings to be powered, then at each later power-up the device will autonomously load the OTP settings and enable the LDO as configured, without requiring communications first.

The BQ76907 is designed to operate properly with a die temperature up to 110°C, therefore the system design must avoid drawing excessive current from the REGOUT LDO if it could result in the die temperature exceeding this level. For example, with a stack voltage of 31.5 V, and REGOUT programmed to an output voltage of 2.5 V, the device will dissipate approximately 580 mW when supplying 20 mA 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 may need to be limited in the system.

The BQ76907 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 will also enter 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 will automatically power on again.