SLVSIU4 April   2026 BQ27Z846

ADVANCE INFORMATION  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configurations and Functions
  6. 5 Specifications
    1. 5.1  Absolute Maximum Ratings
    2. 5.2  ESD Ratings
    3. 5.3  Recommended Operating Conditions
    4. 5.4  Supply Current
    5. 5.5  1.8V LDO Regulator (REG18)
    6. 5.6  Low Frequency Oscillator (LFO)
    7. 5.7  High Frequency Oscillator (HFO)
    8. 5.8  PACK Clamp (PACK_CLAMP)
    9. 5.9  Analog-to-Digital Converter (VADC)
    10. 5.10 Coulomb Counter (CCADC)
    11. 5.11 Coulomb Counter Digital Filter (CC1)
    12. 5.12 Current Measurement Digital Filter (CC2)
    13. 5.13 Wake-up Comparator (I-WAKE)
    14. 5.14 Internal Temperature Sensor (INT_TEMP)
    15. 5.15 Thermistor Measurement Support
    16. 5.16 Hardware-based Protection (SCOMP) Thresholds (OVP, UVP, OCC, OCD, SCD)
    17. 5.17 Hardware-based Protections (SCOMP) Timing (OVP, UVP, OCC, OCD, SCD)
    18. 5.18 CHG, DSG NFET Drivers
    19. 5.19 Zero-volt Charging (ZVCHG)
    20. 5.20 General Purpose Input-Outputs (INT)
    21. 5.21 I2C Interface I/O (SDA, SCL)
    22. 5.22 I2C Interface Timing
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1  BQ27Z855 Processor
      2. 6.3.2  Battery Parameter Measurements
        1. 6.3.2.1 Analog-to-Digital Converter (VADC)
        2. 6.3.2.2 VADC Multiplexer
        3. 6.3.2.3 Coulomb Counter (CCADC) and Digital Filter (CC1)
        4. 6.3.2.4 Internal Temperature Sensor (INT_TEMP)
        5. 6.3.2.5 External Temperature Sensor Support
      3. 6.3.3  Power Supply Control
      4. 6.3.4  ENAB Pin
      5. 6.3.5  I2C Bus Communication Interface
      6. 6.3.6  Low Frequency Oscillator (LFO)
      7. 6.3.7  High Frequency Oscillator (HFO)
      8. 6.3.8  Real Time Clock (RTC)
      9. 6.3.9  1.8V Low Dropout Regulator (REG18)
      10. 6.3.10 FET Drivers (CHG, DSG)
        1. 6.3.10.1 Charge (CHG) FET Driver
        2. 6.3.10.2 Discharge (DSG) FET Driver
      11. 6.3.11 Zero-volt Charging (ZVCHG)
      12. 6.3.12 Integrated Protections
        1. 6.3.12.1 Hardware-based Protections
          1. 6.3.12.1.1 Overvoltage Protection (OVP)
          2. 6.3.12.1.2 Undervoltage Protection (UVP)
          3. 6.3.12.1.3 Overcurrent in Charge Protection (OCC)
          4. 6.3.12.1.4 Overcurrent in Discharge Protection (OCD)
          5. 6.3.12.1.5 Short Circuit Current in Discharge Protection (SCD)
          6. 6.3.12.1.6 Wake-up Comparator (I-WAKE)
        2. 6.3.12.2 Firmware-based Protections
          1. 6.3.12.2.1 Primary Level Protection Features
          2. 6.3.12.2.2 Permanent Failure Protection Features
      13. 6.3.13 Gas Gauging
      14. 6.3.14 Advanced Battery Algorithms
        1. 6.3.14.1 Si-anode Chemistry Support
        2. 6.3.14.2 Internal Short Indication (ISI)
        3. 6.3.14.3 Battery Swelling Detection (BSD)
      15. 6.3.15 Charge Control Features
      16. 6.3.16 Lifetime Data Logging Features
      17. 6.3.17 Authentication
        1. 6.3.17.1 ECC ECDSA Authentication
        2. 6.3.17.2 SHA-256 Authentication
      18. 6.3.18 Over the Air (OTA) Field Updater
      19. 6.3.19 Configuration
        1. 6.3.19.1 Cell Voltage Measurements
        2. 6.3.19.2 Coulomb Counting
        3. 6.3.19.3 Temperature Measurements
    4. 6.4 Device Functional Modes
  8. 7 Application and Implementation
    1. 7.1 Application Information
    2. 7.2 Typical Application Schematics
      1. 7.2.1 Design Requirements
      2. 7.2.2 Detailed Design Procedure
        1. 7.2.2.1 High-Current Path
          1. 7.2.2.1.1 Protection FETs
          2. 7.2.2.1.2 Battery Cell Connections
          3. 7.2.2.1.3 Sense Resistor
          4. 7.2.2.1.4 ESD Mitigation
        2. 7.2.2.2 Gas Gauge Circuit
          1. 7.2.2.2.1 Cell Voltage Measurement Interface
          2. 7.2.2.2.2 Coulomb Counter Interface
          3. 7.2.2.2.3 Temperature Measurement
          4. 7.2.2.2.4 1.8V Low Dropout Regulator (REG18)
          5. 7.2.2.2.5 I2C Communication (SDA, SCL)
          6. 7.2.2.2.6 Interrupt to Host Interface (INT)
        3. 7.2.2.3 Co-design with BQ27Z746 and BQ27Z758
          1. 7.2.2.3.1 Footprint Compatibility and Equivalent Pins
          2. 7.2.2.3.2 Co-layout Example
    3. 7.3 Power Supply Recommendations
  9. 8 Layout
    1. 8.1 Layout Guidelines
  10. 9 Device and Documentation Support
    1. 9.1 Third-Party Products Disclaimer
    2. 9.2 Documentation Support
      1. 9.2.1 Related Documentation
    3. 9.3 Trademarks
    4. 9.4 Electrostatic Discharge Caution
    5. 9.5 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information
    1.     PACKAGE OPTION ADDENDUM
    2. 11.1 Tape and Reel Information
    3. 11.2 Mechanical Data

5.6 Low Frequency Oscillator (LFO)

Typical values stated where TA = 25℃ and VBAT = 3.8V, MIN/MAX values stated where TA = -40℃ to 85℃ and VBAT = 2.0V to 5.0V (unless otherwise noted)
PARAMETERTEST CONDITIONSMINTYPMAXUNIT
FLFOOperating frequency65.536kHz
FLFO_DRIFT(1)(2)Frequency drift-2.52.5%
(1) Specified by Characterization. Not production tested.
(2) The frequency drift is included and measured from the trimmed frequency at TA = 25°C, with the minimum and maximum based on Characterization, actual value stored in OTP