SLUSBV4B June   2018  – September 2020 BQ40Z80

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Description (continued)
  6. 6 Pin Configuration and Functions
    1.     Pin 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
    5. 7.5 Electrical Characteristics
    6. 7.6 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1  Primary (1st Level) Safety Features
      2. 8.3.2  Secondary (2nd Level) Safety Features
      3. 8.3.3  Charge Control Features
      4. 8.3.4  Gas Gauging
      5. 8.3.5  Multifunction Pins
      6. 8.3.6  Configuration
        1. 8.3.6.1 Oscillator Function
        2. 8.3.6.2 System Present Operation
        3. 8.3.6.3 Emergency Shutdown
        4. 8.3.6.4 2-Series, 3-Series, 4-Series, 5-Series, or 6-Series Cell Configuration
        5. 8.3.6.5 Cell Balancing
      7. 8.3.7  Battery Parameter Measurements
        1. 8.3.7.1 Charge and Discharge Counting
      8. 8.3.8  Lifetime Data Logging Features
      9. 8.3.9  Authentication
      10. 8.3.10 LED Display
      11. 8.3.11 IATA Support
      12. 8.3.12 Voltage
      13. 8.3.13 Current
      14. 8.3.14 Temperature
      15. 8.3.15 Communications
        1. 8.3.15.1 SMBus On and Off State
        2. 8.3.15.2 SBS Commands
    4. 8.4 Device Functional Modes
  9. 9 Applications and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Applications
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Using the BQ40Z80EVM with BQSTUDIO
        2. 9.2.2.2 High-Current Path
          1. 9.2.2.2.1 Protection FETs
          2. 9.2.2.2.2 Chemical Fuse
          3. 9.2.2.2.3 Lithium-Ion Cell Connections
          4. 9.2.2.2.4 Sense Resistor
          5. 9.2.2.2.5 ESD Mitigation
        3. 9.2.2.3 Gas Gauge Circuit
          1. 9.2.2.3.1 Coulomb-Counting Interface
          2. 9.2.2.3.2 Power Supply Decoupling and PBI
          3. 9.2.2.3.3 System Present
          4. 9.2.2.3.4 SMBus Communication
          5. 9.2.2.3.5 FUSE Circuitry
        4. 9.2.2.4 Secondary-Current Protection
          1. 9.2.2.4.1 Cell and Battery Inputs
          2. 9.2.2.4.2 External Cell Balancing
          3. 9.2.2.4.3 PACK and FET Control
          4. 9.2.2.4.4 Pre-Discharge Control
          5. 9.2.2.4.5 Temperature Output
          6. 9.2.2.4.6 LEDs
      3. 9.2.3 Application Curve
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
      1. 11.1.1 Protector FET Bypass and Pack Terminal Bypass Capacitors
      2. 11.1.2 ESD Spark Gap
    2. 11.2 Layout Examples
  12. 12Device and Documentation Support
    1. 12.1 Documentation Support
      1. 12.1.1 Related Documentation
    2. 12.2 Receiving Notification of Documentation Updates
    3. 12.3 Support Resources
    4. 12.4 Trademarks
    5. 12.5 Electrostatic Discharge Caution
    6. 12.6 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information
9.2.2.2.3 Lithium-Ion Cell Connections

The important part about the cell connections is that high current flows through the top and bottom connections; therefore, the voltage sense leads at these points must be made with a Kelvin connection to avoid any errors due to a drop in the high-current copper trace. The location marked 6P indicates the Kelvin connection of the most positive directly measured battery node. The single-point connection at 1N to the low-current ground is needed to avoid an undesired voltage drop through long traces while the gas gauge is measuring the bottom cell voltage.