SLUSE14B December   2020  – December 2021 BQ76942

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Device Comparison Table
  6. 6 Pin Configuration and Functions
  7. 7 Specifications
    1. 7.1  Absolute Maximum Ratings
    2. 7.2  ESD Ratings
    3. 7.3  Recommended Operating Conditions
    4. 7.4  Thermal Information BQ76942
    5. 7.5  Supply Current
    6. 7.6  Digital I/O
    7. 7.7  LD Pin
    8. 7.8  Precharge (PCHG) and Predischarge (PDSG) FET Drive
    9. 7.9  FUSE Pin Functionality
    10. 7.10 REG18 LDO
    11. 7.11 REG0 Pre-regulator
    12. 7.12 REG1 LDO
    13. 7.13 REG2 LDO
    14. 7.14 Voltage References
    15. 7.15 Coulomb Counter
    16. 7.16 Coulomb Counter Digital Filter (CC1)
    17. 7.17 Current Measurement Digital Filter (CC2)
    18. 7.18 Current Wake Detector
    19. 7.19 Analog-to-Digital Converter
    20. 7.20 Cell Balancing
    21. 7.21 Cell Open Wire Detector
    22. 7.22 Internal Temperature Sensor
    23. 7.23 Thermistor Measurement
    24. 7.24 Internal Oscillators
    25. 7.25 High-Side NFET Drivers
    26. 7.26 Comparator-Based Protection Subsystem
    27. 7.27 Timing Requirements – I2C Interface, 100kHz Mode
    28. 7.28 Timing Requirements – I2C Interface, 400kHz Mode
    29. 7.29 Timing Requirements – HDQ Interface
    30. 7.30 Timing Requirements – SPI Interface
    31. 7.31 Interface Timing Diagrams
    32. 7.32 Typical Characteristics
  8. 8 Device Description
    1. 8.1 Overview
    2. 8.2 BQ76942 Device Versions
    3. 8.3 Functional Block Diagram
    4. 8.4 Diagnostics
  9. 9 Device Configuration
    1. 9.1 Commands and Subcommands
    2. 9.2 Configuration Using OTP or Registers
    3. 9.3 Device Security
    4. 9.4 Scratchpad Memory
  10. 10Measurement Subsystem
    1. 10.1  Voltage Measurement
      1. 10.1.1 Voltage Measurement Schedule
      2. 10.1.2 Usage of VC Pins for Cells Versus Interconnect
      3. 10.1.3 Cell 1 Voltage Validation During SLEEP Mode
    2. 10.2  General Purpose ADCIN Functionality
    3. 10.3  Coulomb Counter and Digital Filters
    4. 10.4  Synchronized Voltage and Current Measurement
    5. 10.5  Internal Temperature Measurement
    6. 10.6  Thermistor Temperature Measurement
    7. 10.7  Factory Trim of Voltage ADC
    8. 10.8  Voltage Calibration (ADC Measurements)
    9. 10.9  Voltage Calibration (COV and CUV Protections)
    10. 10.10 Current Calibration
    11. 10.11 Temperature Calibration
  11. 11Primary and Secondary Protection Subsystems
    1. 11.1 Protections Overview
    2. 11.2 Primary Protections
    3. 11.3 Secondary Protections
    4. 11.4 High-Side NFET Drivers
    5. 11.5 Protection FETs Configuration and Control
      1. 11.5.1 FET Configuration
      2. 11.5.2 PRECHARGE and PREDISCHARGE Modes
    6. 11.6 Load Detect Functionality
  12. 12Device Hardware Features
    1. 12.1  Voltage References
    2. 12.2  ADC Multiplexer
    3. 12.3  LDOs
      1. 12.3.1 Preregulator Control
      2. 12.3.2 REG1 and REG2 LDO Controls
    4. 12.4  Standalone Versus Host Interface
    5. 12.5  Multifunction Pin Controls
    6. 12.6  RST_SHUT Pin Operation
    7. 12.7  CFETOFF, DFETOFF, BOTHOFF Pin Functionality
    8. 12.8  ALERT Pin Operation
    9. 12.9  DDSG and DCHG Pin Operation
    10. 12.10 Fuse Drive
    11. 12.11 Cell Open Wire
    12. 12.12 Low Frequency Oscillator
    13. 12.13 High Frequency Oscillator
  13. 13Device Functional Modes
    1. 13.1 Overview
    2. 13.2 NORMAL Mode
    3. 13.3 SLEEP Mode
    4. 13.4 DEEPSLEEP Mode
    5. 13.5 SHUTDOWN Mode
    6. 13.6 CONFIG_UPDATE Mode
  14. 14Serial Communications Interface
    1. 14.1 Serial Communications Overview
    2. 14.2 I2C Communications Subsystem
    3. 14.3 SPI Communications Interface
      1. 14.3.1 SPI Protocol
    4. 14.4 HDQ Communications Interface
  15. 15Cell Balancing
    1. 15.1 Cell Balancing Overview
  16. 16Application and Implementation
    1. 16.1 Application Information
    2. 16.2 Typical Applications
      1. 16.2.1 Design Requirements (Example)
      2. 16.2.2 Detailed Design Procedure
      3. 16.2.3 Application Performance Plot
      4. 16.2.4 Calibration Process
      5. 16.2.5 Design Example
    3. 16.3 Random Cell Connection Support
    4. 16.4 Startup Timing
    5. 16.5 FET Driver Turn-Off
    6. 16.6 Unused Pins
  17. 17Power Supply Requirements
  18. 18Layout
    1. 18.1 Layout Guidelines
    2. 18.2 Layout Example
  19. 19Device and Documentation Support
    1. 19.1 Third-Party Products Disclaimer
    2. 19.2 Documentation Support
      1. 19.2.1 Receiving Notification of Documentation Updates
    3. 19.3 Support Resources
    4. 19.4 Trademarks
    5. 19.5 Electrostatic Discharge Caution
    6. 19.6 Glossary
  20. 20Mechanical, Packaging, Orderable Information

Package Options

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

16.6 Unused Pins

Some device pins may not be needed in a particular application. The manner in which each should be terminated in this case is described below.

Table 16-3 Terminating Unused Pins
Pin Name Recommendation
2, 4, 6, 8, 10, 12–16, 48 VC0 – VC10 Cell inputs 1, 2, and 10 should always be connected to actual cells with cells connected between VC1 and VC0, between VC2 and VC1, and VC10 and VC9. VC0 should be connected through a resistor and capacitor on the pcb to pin 17 (VSS). Pins related to any unused cells (which may be cell 3–cell 9) can be connected to the cell stack to measure interconnect resistance or provide a Kelvin-connection to actual cells, in which case they should include a series resistor and parallel capacitor in similar fashion to pins connected to actual cells (see Usage of VC Pins for Cells Versus Interconnect). Another option is to short unused VC pins directly to an adjacent VC pin. All VC pins should be connected to either an adjacent VC pin, an actual cell (through R and C), or stack interconnect resistance (through R and C).
18, 20 SRP, SRN If not used, these pins should be connected to pin 17 (VSS).
1, 3, 5, 7, 9, 11, 19, 44 NC These pins are not connected to silicon. They can be left floating or connected to an adjacent pin or connected to VSS.
21, 23, 25, 28, 29, 30, 31, 32 TS1, TS3, ALERT, HDQ, CFETOFF, DFETOFF, DCHG, DDSG If not used, these pins can be left floating or connected to pin 17 (VSS). Any of these pins (except for TS1 and TS3) may be configured with the internal weak pulldown resistance enabled during operation, although this is not necessary.
22 TS2 If the device is intended to enter SHUTDOWN mode, the TS2 pin should be left floating. If SHUTDOWN mode is not used in the application and the TS2 pin is not used for a thermistor or ADCIN measurement, the TS2 pin can be left floating or connected to pin 17 (VSS).
33 RST_SHUT If not used, this pin should be connected to pin 17 (VSS).
34, 35 REG1, REG2 If not used, these pins can be left floating or connected to pin 17 (VSS).
36 REGIN If not used, this pin should be connected to pin 17 (VSS).
37 BREG If this pin is not used and pin 36 (REGIN) is also not used, both pins should be connected to pin 17 (VSS). If this pin is not used but pin 36 is used (such as driven from an external source), then this pin should be connected to pin 36 (REGIN).
38 FUSE If not used, this pin can be left floating or connected to pin 17 (VSS).
39 PDSG If not used, this pin should be left floating.
40 PCHG If not used, this pin should be left floating.
41 LD If the DSG driver is not used, this pin can be connected through a series resistor to the PACK+ connector or can be connected to pin 17 (VSS).
43 DSG If not used, this pin should be left floating.
45 CHG If not used, this pin should be left floating.
46 CP1 If not used, this pin should be connected to pin 47 (BAT). Note: If the charge pump is enabled with CP1 connected to BAT, the device consumes an additional ≈200 µA.