BQ20Z45-R1 is not recommended for new designs.
This product continues to be in production to support existing customers. Please consider one of these alternatives:
Same functionality with different pin-out to the compared device.
BQ40Z50-R2 ACTIVE 1-4 series Li-ion battery pack manager supporting Turbo Mode 2.0 Improved hardware and firmware with a smaller package.

Product details


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  • Next Generation Patented Impedance Track Technology Accurately Measures Available Charge in Li-Ion and Li-Polymer Batteries
    • Better Than 1% Error Over the Lifetime of the Battery
  • Supports the Smart Battery Specification SBS V1.1
  • Flexible Configuration for 2 to 4 Series Li-Ion and Li-Polymer Cells
  • Powerful 8-Bit RISC CPU With Ultralow Power Modes
  • Full Array of Programmable Protection Features
    • Voltage, Current, and Temperature
  • Satisfies JEITA Guidelines
  • Added Flexibility to Handle More Complex Charging Profiles
  • Lifetime Data Logging
  • Supports SHA-1 Authentication
  • Complete Battery Protection and Gas Gauge Solution in One Package
  • Available in a 38-Pin TSSOP (DBT) package
    • Notebook PCs
    • Medical and Test Equipment
    • Portable Instrumentation
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The bq20z45-R1 SBS-compliant gas gauge and protection IC is a single IC solution designed for battery-pack or in-system installation. The bq20z45-R1 measures and maintains an accurate record of available charge in Li-ion or Li-polymer batteries using its integrated high-performance analog peripherals, monitors capacity change, battery impedance, open-circuit voltage, and other critical parameters of the battery pack as well and reports the information to the system host controller over a serial-communication bus. Together with the integrated analog front-end (AFE) short-circuit and overload protection, the bq20z45-R1 maximizes functionality and safety while minimizing external component count, cost, and size in smart battery circuits.

The implemented Impedance Track™ gas gauging technology continuously analyzes the battery impedance, resulting in superior gas-gauging accuracy. This enables remaining capacity to be calculated with discharge rate, temperature, and cell aging all accounted for during each stage of every cycle with high accuracy.

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Technical documentation

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Type Title Date
* Data sheet SBS 1.1-Compliant Gas Gauge & Protection Enabled With Impedance Track datasheet Dec. 22, 2009
Application note Wide-Vin Battery-Charger Using SMBus MSP430 MCUs and bq Fuel Gauges (Rev. B) Jul. 12, 2019
Application note Configuring the bq20z40/bq20z45 Data Flash (Rev. B) Nov. 11, 2013
Application note Data Flash Programing and Calibrating the bq20zxx Family of Gas Gauges (Rev. E) Sep. 14, 2013
Technical article Giving More Life to LiFePO4 Batteries Sep. 13, 2013
Application note Thermistor Selection Guide for Texas Instruments Advanced Fuel Gauges Sep. 28, 2011
User guide bq20z40-R1/45-R1 Technical Reference Manual (Rev. A) Mar. 18, 2011
Application note BQ20Z40/45 to BQ20Z40-R1/45-R1 change document Feb. 23, 2011
Application note Cell Balancing Using the bq20zxx (Rev. C) Jan. 12, 2011
Application note bq20z40/45/60/65 Printed-Circuit Board Layout Guide Dec. 03, 2009
Application note Design 4: Support of Multiple Li-Ion Chemistries w/Impedance Track(TM) Gas Gauge (Rev. R) Oct. 15, 2009
Application note bq20z40/45 and bq20z60/65 Gas Gauge Circuit Design Aug. 10, 2009
Application note bq20z40/45 and bq20z60/65 EVM Data Flash Settings for Number of Serial Cells Aug. 07, 2009
Application note bq20z40/bq20z45 and bq20z60/bq20z65 Data Flash Comparison Jul. 09, 2009
Application note bq20z40/bq20z45 Change List Jun. 29, 2009
User guide bq20z45EVM-001 SBS 1.1 Impedance Track Technology Enabled Battery Mgmt Sol EVM (Rev. C) Jun. 24, 2009
Application note Fast Cell Balancing Using External MOSFET (Rev. A) Jan. 26, 2009
Application note Information to Provide When Reporting Issues With TI Gauges Jul. 18, 2008
Application note Quick-Start Guide for bq20zxx Family Gas Gauges (Rev. A) Sep. 04, 2007
Application note bq20z70 and bq20z90 Application Book Dec. 13, 2006
Application note Pack Assembly and the bq20zxx (Rev. B) Nov. 07, 2006
Application note Thermistor Coefficient Calculator for TI Advanced Fuel Gauges Oct. 04, 2006
Application note Battery Pack Production Flow With bq20zXX Aug. 02, 2006
Application note Design 2: Avoiding ESD and EMI Problems in bq20zxx Battery Pack Electronics Nov. 11, 2005

Design & development

For additional terms or required resources, click any title below to view the detail page where available.

Hardware development

document-generic User guide

The Texas Instruments Advanced bqMTester Multi-Station Test and Program Board is designed to calibrate and program electronic smart battery modules based on the latest Texas Instruments advanced battery gas gauges (BQ20z40 (...)

  • Programs and Calibrates Smart Battery Modules Based on the Following Devices: BQ20z40 (...)
document-generic User guide

This solution, available from MKS Technology, is an alternative for the EV2300 communications transceiver. The solution from MKS Technology has been validated and works with both the BQMTESTER and ADVANCED-BQMTESTER. It has been validated and works with bq Evaluation software (bqEVSW). Using the MKS (...)

Software development

BQ20Z45-R1 bqEASY Software
BQ20Z45-R1_BQEASY-SW bqEASY is a tool that simplifies the bq gas gauge configuration and parameter optimize process.
  • Ensure to start with a known good data flash
  • Simplify DF configuration
  • Guide through device calibration
  • Help to select the right chemistry
  • Learn correct battery Qmax and Resistance
SLUC261HY.ZIP (496964 KB)

Design tools & simulation

Gas Gauge Chemistry Updater
GASGAUGECHEM-SW The Chemistry Updater installer contains data used by the bq Evaluation/ bqEVSW / bqEASY tool for selecting the correct or closest chemical identification file for your battery pack.

The Battery Management Studio (bqStudio) chemistry update zip file contains data used by bqStudio for selecting the (...)
document-generic User guide
SLUC138DJ.ZIP (6840 KB)

CAD/CAE symbols

Package Pins Download
TSSOP (DBT) 38 View options

Ordering & quality

Information included:
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  • Device marking
  • Lead finish/Ball material
  • MSL rating/Peak reflow
  • MTBF/FIT estimates
  • Material content
  • Qualification summary
  • Ongoing reliability monitoring

Support & training

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