SLUSA52C September 2010  – March 2016


  1. Features
  2. Applications
  3. Description
  4. Revision History
  5. Device Options
  6. Pin Configuration and Functions
  7. Specifications
    1. 7.1Absolute Maximum Ratings
    2. 7.2ESD Ratings
    3. 7.3Recommended Operating Conditions
    4. 7.4Thermal Information
    5. 7.5Electrical Characteristics
    6. 7.6Recommended Cell Balancing Configurations
    7. 7.7Typical Characteristics
  8. Detailed Description
    1. 8.1Overview
      1. 8.1.1Voltage Protection
      2. 8.1.2Cell Balancing
    2. 8.2Functional Block Diagram
    3. 8.3Feature Description
      1. 8.3.1Protection (OUT) Timing
      2. 8.3.2Cell Voltage > VPROTECT
      3. 8.3.3Cell Connection Sequence
      4. 8.3.4Cell Balance Enable Control
      5. 8.3.5Cell Balance Configuration
      6. 8.3.6Cell Imbalance Auto-Detection (Via Cell Voltage)
      7. 8.3.7Customer Test Mode
      8. 8.3.8Test Conditions
    4. 8.4Device Functional Modes
      1. 8.4.1NORMAL Mode
      2. 8.4.2PROTECTION Mode
  9. Application and Implementation
    1. 9.1Application Information
    2. 9.2Typical Applications
      1. 9.2.1Battery Connection
        1. Requirements
        2. Design Procedure
        3. Curve
    3. 9.3System Example
      1. 9.3.1External Cell Balancing
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1Layout Guidelines
    2. 11.2Layout Example
  12. 12Device and Documentation Support
    1. 12.1Related Links
    2. 12.2Community Resources
    3. 12.3Trademarks
    4. 12.4Electrostatic Discharge Caution
    5. 12.5Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • DRB|8
Orderable Information

1 Features

  • 2-Series Cell Secondary Protection
  • Automatic Cell Imbalance Correction with External Enable Control
    • ±30-mV Enable, 0-mV Disable Thresholds Typical
  • External Capacitor-Controlled Delay Timer
  • External Resistor-Controlled Cell Balance Current
  • Low Power Consumption ICC < 3 µA Typical (VCELL(ALL) < VPROTECT)
  • Internal Cell Balancing Handles Current
    up to 15 mA
  • External Cell Balancing Mode Supported
  • High-Accuracy Overvoltage Protection:
    • ±25 mV with TA = 0°C to 60°C
  • Fixed Overvoltage Protection Thresholds:
    4.30 V, 4.35 V
  • Small 8L DRB Package

2 Applications

  • 2nd Level Protection in Li-Ion Battery Packs
    • Netbook Computers
    • Power Tools
    • Portable Equipment and Instrumentation
    • Battery Backup Systems

3 Description

The bq2920x device is a secondary overvoltage protection IC for 2-series cell lithium-ion battery packs that incorporates a high-accuracy precision overvoltage detection circuit and automatic cell imbalance correction.

The voltage of each cell in a 2-series cell battery pack is compared to a factory programmed internal reference voltage. If either cell reaches an overvoltage condition, the OUT pin changes from low to high state.

The bq2920x can perform automatic voltage-based cell imbalance correction. Balancing can start when the cell voltages are different by nominally 30 mV or more and stops when the difference is nominally 0 mV. Cell balancing is enabled and disabled by the CB_EN pin.

Device Information(1)

bq29200VSON (8)3.00 mm × 3.00 mm
  1. For all available packages, see the orderable addendum at the end of the datasheet.

Simplified Schematic

bq29200 bq29209 cell_conf_lusa52.gif