SLVSLM6 May   2026 BQ76972-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 BQ76972-Q1
    5. 6.5  Supply Current
    6. 6.6  Digital I/O
    7. 6.7  LD Pin
    8. 6.8  Precharge (PCHG) and Predischarge (PDSG) FET Drive
    9. 6.9  FUSE Pin Functionality
    10. 6.10 REG18 LDO
    11. 6.11 REG0 Pre-regulator
    12. 6.12 REG1 LDO
    13. 6.13 REG2 LDO
    14. 6.14 Voltage References
    15. 6.15 Coulomb Counter
    16. 6.16 Coulomb Counter Digital Filter (CC1)
    17. 6.17 Current Measurement Digital Filter (CC2)
    18. 6.18 Current Wake Detector
    19. 6.19 Analog-to-Digital Converter
    20. 6.20 Cell Voltage Measurement Accuracy
    21. 6.21 Multifunction Pin ADC Measurement
    22. 6.22 Cell Balancing
    23. 6.23 Cell Open Wire Detector
    24. 6.24 Internal Temperature Sensor
    25. 6.25 Thermistor Measurement
    26. 6.26 Internal Oscillators
    27. 6.27 High-side NFET Drivers
    28. 6.28 Comparator-Based Protection Subsystem
    29. 6.29 Timing Requirements - I2C Interface, 100kHz Mode
    30. 6.30 Timing Requirements - I2C Interface, 400kHz Mode
    31. 6.31 Timing Requirements - HDQ Interface
    32. 6.32 Timing Requirements - SPI Interface
    33. 6.33 Interface Timing Diagrams
    34. 6.34 Typical Characteristics
  8. 7 Detailed Description
    1. 7.1  Overview
    2. 7.2  Functional Block Diagram
    3. 7.3  Diagnostics
    4. 7.4  Device Configuration
      1. 7.4.1 Commands and Subcommands
      2. 7.4.2 Configuration Using OTP or Registers
      3. 7.4.3 Device Security
      4. 7.4.4 Scratchpad Memory
    5. 7.5  Measurement Subsystem
      1. 7.5.1  Voltage Measurement
        1. 7.5.1.1 Voltage Measurement Schedule
        2. 7.5.1.2 Usage of VC Pins for Cells Versus Interconnect
        3. 7.5.1.3 Cell 1 Voltage Validation During SLEEP Mode
      2. 7.5.2  General Purpose ADCIN Functionality
      3. 7.5.3  Coulomb Counter and Digital Filters
      4. 7.5.4  Synchronized Voltage and Current Measurement
      5. 7.5.5  Internal Temperature Measurement
      6. 7.5.6  Thermistor Temperature Measurement
      7. 7.5.7  Factory Trim of Voltage ADC
      8. 7.5.8  Cell Voltage Measurement Accuracy
        1. 7.5.8.1 Cell Offset Calibration
      9. 7.5.9  Voltage Calibration (ADC Measurements)
      10. 7.5.10 Voltage Calibration (COV and CUV Protections)
      11. 7.5.11 Current Calibration
      12. 7.5.12 Temperature Calibration
    6. 7.6  Primary and Secondary Protection Subsystems
      1. 7.6.1 Protections Overview
      2. 7.6.2 Primary Protections
      3. 7.6.3 Secondary Protections
      4. 7.6.4 High-Side NFET Drivers
      5. 7.6.5 Protection FETs Configuration and Control
        1. 7.6.5.1 FET Configuration
        2. 7.6.5.2 PRECHARGE and PREDISCHARGE Modes
      6. 7.6.6 Load Detect Functionality
    7. 7.7  Device Hardware Features
      1. 7.7.1  Voltage References
      2. 7.7.2  ADC Multiplexer
      3. 7.7.3  LDOs
        1. 7.7.3.1 Preregulator Control
        2. 7.7.3.2 REG1 and REG2 LDO Controls
      4. 7.7.4  Standalone Versus Host Interface
      5. 7.7.5  Multifunction Pin Controls
      6. 7.7.6  RST_SHUT Pin Operation
      7. 7.7.7  CFETOFF, DFETOFF, and BOTHOFF Pin Functionality
      8. 7.7.8  ALERT Pin Operation
      9. 7.7.9  DDSG and DCHG Pin Operation
      10. 7.7.10 Fuse Drive
      11. 7.7.11 Cell Open Wire
      12. 7.7.12 Low Frequency Oscillator
      13. 7.7.13 High Frequency Oscillator
    8. 7.8  Device Functional Modes
      1. 7.8.1 Overview
      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. 7.9  Serial Communications Interface
      1. 7.9.1 Serial Communications Overview
      2. 7.9.2 I2C Communications
      3. 7.9.3 SPI Communications
        1. 7.9.3.1 SPI Protocol
      4. 7.9.4 HDQ Communications
    10. 7.10 Cell Balancing
      1. 7.10.1 Cell Balancing Overview
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 Design Requirements (Example)
      2. 8.2.2 Detailed Design Procedure
      3. 8.2.3 Application Performance Plot
      4. 8.2.4 Calibration Process
    3. 8.3 Random Cell Connection Support
    4. 8.4 Startup Timing
    5. 8.5 FET Driver Turn-Off
    6. 8.6 Unused Pins
    7. 8.7 Power Supply Requirements
    8. 8.8 Layout
      1. 8.8.1 Layout Guidelines
      2. 8.8.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Documentation Support
      1. 9.1.1 Related Documentation
    2. 9.2 Support Resources
    3. 9.3 Trademarks
    4. 9.4 Electrostatic Discharge Caution
    5. 9.5 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, Orderable Information

8.4 Startup Timing

At initial power up of the BQ76972-Q1 device from a SHUTDOWN state, the device progresses through a sequence of events before entering NORMAL mode operation. These are described below for an example configuration, with approximate timing shown for the cases when [FASTADC] = 0 and [FASTADC] = 1.

Note: When the device is configured for autonomous FET control (that is, [FET_EN] = 1), the decision to enable FETs is only evaluated every 250ms while in NORMAL mode, which is why the FETs are not enabled until approximately 280ms after the wakeup event, even though the data was available earlier.
Table 8-2 Startup Sequence and Timing
STEPCOMMENTFASTADC SETTINGTIME (RELATIVE TO WAKEUP EVENT)
Wakeup eventEither the TS2 pin is pulled low or the LD pin is pulled up, triggering the device to exit SHUTDOWN mode.0, 10
REG1 poweredThis is measured with the OTP programmed to autonomously power the REG1 LDO.0, 120ms
INITSTART assertedThis is measured with the OTP programmed to provide the INITSTART bit in the Alarm signal on the ALERT pin.0, 123ms
INITCOMP and ADSCAN assertedThis is measured with the OTP programmed to provide the INITCOMP and ADSCAN bits in the Alarm signal on the ALERT pin.088ms
158ms
FULLSCAN assertedThis is measured with the OTP programmed to provide the FULLSCAN bit in the Alarm signal on the ALERT pin.0221ms
1129ms
FETs enabledThis is measured with the OTP programmed to autonomously enable FETs.0282ms
1284ms

Figure 8-5 shows an example of an oscilloscope plot of a startup sequence with the device configured in OTP with [FASTADC] = 1, [FET_EN] = 1 for autonomous FET control, setup to use three thermistors, and providing the [INITCOMP] flag on the ALERT pin. The TS2 pin is pulled low to initiate device wakeup from SHUTDOWN.


BQ76972-Q1 Startup Sequence Using [FASTADC] = 1, with the [INITCOMP] Flag Displayed on the ALERT Pin

Figure 8-5 Startup Sequence Using [FASTADC] = 1, with the [INITCOMP] Flag Displayed on the ALERT Pin