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BQ27421-G1

ACTIVE

System-side(tm) fuel gauge with integrated Sense Resistor | battery gas gauge

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Data sheet
User guides

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Same functionality with different pin-out to the compared device
BQ27427 ACTIVE Single-cell battery fuel gauge with pre-programmed chemistry and integrated sense resistor Low power consumption, internal sense resistor and battery state-of-health (aging) estimates

BQ27421-G1

ACTIVE
Data sheet Order now

Product details

Cell chemistry Li-Ion/Li-Polymer Number of series cells Single Cell Communication interface I2C Battery capacity (min) (mAh) 100 Battery capacity (max) (mAh) 8000 Implementation System External capacity indication None Features Impedance Track™ algorithm, Integrated Sense Resistor Operating temperature range (°C) -40 to 85 Rating Catalog
Cell chemistry Li-Ion/Li-Polymer Number of series cells Single Cell Communication interface I2C Battery capacity (min) (mAh) 100 Battery capacity (max) (mAh) 8000 Implementation System External capacity indication None Features Impedance Track™ algorithm, Integrated Sense Resistor Operating temperature range (°C) -40 to 85 Rating Catalog
DSBGA (YZF) 9 3.0625 mm² 1.75 x 1.75
  • Single-Cell Li-Ion Battery Fuel Gauge
    • Resides on System Board
    • Supports Embedded or Removable Batteries
    • Powered Directly from Battery with Integrated
      LDO
    • Low-Value Integrated Sense Resistor
      (7 mΩ, Typical)
  • Easy-to-Configure Fuel Gauging Based on
    Patented Impedance Track™ Technology
    • Reports Remaining Capacity and State-of-
      Charge (SOC) with Smoothing Filter
    • Automatically Adjusts for Battery Aging, Self-
      Discharge, Temperature, and Rate Changes
    • Battery State-of-Health (Aging) Estimation
  • Microcontroller Peripheral Supports:
    • 400-kHz I2C Serial Interface
    • Configurable SOC Interrupt or
      Battery Low Digital Output Warning
    • Internal Temperature Sensor or
      Host-Reported Temperature
  • Single-Cell Li-Ion Battery Fuel Gauge
    • Resides on System Board
    • Supports Embedded or Removable Batteries
    • Powered Directly from Battery with Integrated
      LDO
    • Low-Value Integrated Sense Resistor
      (7 mΩ, Typical)
  • Easy-to-Configure Fuel Gauging Based on
    Patented Impedance Track™ Technology
    • Reports Remaining Capacity and State-of-
      Charge (SOC) with Smoothing Filter
    • Automatically Adjusts for Battery Aging, Self-
      Discharge, Temperature, and Rate Changes
    • Battery State-of-Health (Aging) Estimation
  • Microcontroller Peripheral Supports:
    • 400-kHz I2C Serial Interface
    • Configurable SOC Interrupt or
      Battery Low Digital Output Warning
    • Internal Temperature Sensor or
      Host-Reported Temperature

The Texas Instruments bq27421-G1 fuel gauge is a minimally configured microcontroller peripheral that provides system-side fuel gauging for single-cell Li-Ion batteries. The device requires very little user configuration and system microcontroller firmware development.

The bq27421-G1 fuel gauge uses the patented Impedance TrackTM algorithm for fuel gauging, and provides information such as remaining battery capacity (mAh), state-of-charge (%), and battery voltage (mV).

Battery fuel gauging with the bq27421-G1 fuel gauge requires connections only to PACK+ (P+) and PACK– (P–) for a removable battery pack or embedded battery circuit. The tiny 9-ball, 1.62 mm × 1.58 mm, 0.5-mm pitch NanoFree™ chip scale package (DSBGA) is ideal for space-constrained applications.

The Texas Instruments bq27421-G1 fuel gauge is a minimally configured microcontroller peripheral that provides system-side fuel gauging for single-cell Li-Ion batteries. The device requires very little user configuration and system microcontroller firmware development.

The bq27421-G1 fuel gauge uses the patented Impedance TrackTM algorithm for fuel gauging, and provides information such as remaining battery capacity (mAh), state-of-charge (%), and battery voltage (mV).

Battery fuel gauging with the bq27421-G1 fuel gauge requires connections only to PACK+ (P+) and PACK– (P–) for a removable battery pack or embedded battery circuit. The tiny 9-ball, 1.62 mm × 1.58 mm, 0.5-mm pitch NanoFree™ chip scale package (DSBGA) is ideal for space-constrained applications.
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Technical documentation

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Type Title Date
* Data sheet bq27421-G1 System-Side Impedance Track Fuel Gauge With Integrated Sense Resistor datasheet (Rev. E) PDF | HTML 06 Jan 2016
* User guide bq27421-G1 Technical Reference Manual (Rev. C) 30 Aug 2016
Technical article Get smart: How intelligent battery gauges improve battery life in continuous gluco PDF | HTML 19 Apr 2019
Application note Achieving The Successful Learning Cycle 19 Jun 2018
Application note Simple Guide to Chemical ID Selection Tool (GPC) (Rev. A) 05 Jun 2018
Application note Gauge Communication 12 Jan 2017
Application note Theory and Implementation of Impedance Track Battery Fuel-Gauging Algorithm (Rev. A) PDF | HTML 16 May 2014
More literature Quickstart Guide for bq27421-G1 (Rev. B) 06 May 2014
Application note Verification and Accuracy Test Methods of Gas Gauges 05 Jun 2013
Application note Going to Production With the bq274xx Family of Gas Gauges 27 Jun 2011

Design & development

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

Evaluation board

BQ27421EVM-G1A — BQ27421EVM-G1A System-Side Battery Fuel (Gas) Gauge Evaluation Module Board

System-Side Battery Fuel (Gas) Gauge Solution Evaluation Module

The BQ27421EVM-G1A evaluation module is a complete evaluation system for the bq27421. The EVM includes one bq27421 circuit module with an integrated current-sense resistor. A separated orderable EV2400 PC interface board for gas gauge (...)
User guide: PDF
Not available on TI.com
Evaluation board

BQ27421EVM-G1B — BQ27421EVM-G1B System-Side Battery Fuel (Gas) Gauge Evaluation Module

System-Side Battery Fuel (Gas) Gauge Solution Evaluation Module

The BQ27421EVM-G1B evaluation module is a complete evaluation system for the bq27421. The EVM includes one bq27421 circuit module with an integrated current-sense resistor. A separated orderable EV2300 or EV2400 PC interface board for (...)
User guide: PDF
Not available on TI.com
Interface adapter

EV2400 — USB-Based PC Interface Board for Battery Fuel (Gas) Gauge Evaluation Module

The EV2400 EVM interface board enables an IBM-compatible or other type PC (with the required driver for its particular platform) to communicate with the Texas Instruments SMBus or I2C interface gas gauges via a Universal Serial Bus (USB) port. In addition to this board, PC software is required to (...)

User guide: PDF
Not available on TI.com
Application software & framework

BQSTUDIO — Battery Management Studio (bqStudio) Software

Battery Management Studio (bqStudio) offers a full suite of robust tools to assist with the process of evaluating, designing with, configuring, testing, or otherwise utilizing TI Battery management products. This includes features that provide full access to registers and data memory including (...)
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Driver or library

BQ27XXXSW-LINUX — Linux Driver for BQ27XXX

The Linux driver supports the BQ27x series of Battery Fuel Gauges. The Linux driver supports communication through the I2C/HDQ bus and interfaces with the power supply sub-system to monitor battery properties.

 

Linux Mainline Status

Available in Linux Main line: Yes
Available through git.ti.com: N/A

(...)


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Support software

BQEVSW-MKST-UPDATE — Software Update to enable BQEVSW to use MKST-3P-ALT-EV2300

BQ-BATTERY-PROGRAMMER-SW software development kit (SDK) is a collection of robust software command line tools that assist with the process of programming, testing, or assembling packs that use TI Battery management products. The executables in this software work with the MKST-3P-ALT-EV2300 MKS (...)

Supported products & hardware

Supported products & hardware

Products
Battery fuel gauges
BQ2083-V1P3 — SBS-compliant gas gauge for use with bq29311 BQ20Z40 — SBS Compliant Gas Gauge with Impedance Track Technology for use with BQ29330 BQ20Z40-R1 — SBS 1.1 compliant Gas Gauge with Impedance Track™ Technology BQ20Z70-V150 — SBS 1.1-compliant gas gauge enabled with Impedance Track™ technology BQ20Z70-V160 — SBS 1.1-compliant gas gauge enabled with Impedance Track™ technology for use with the bq29330 BQ20Z80 — SBS 1.1-compliant gas gauge enabled with Impedance Track™; technology for use with the bq29312 BQ20Z80-V102 — SBS 1.1-compliant gas gauge enabled w/Impedance Track™ technology BQ20Z80-V110 — SBS 1.1-compliant gas gauge enabled w/Impedance Track™ technology with FW v1.10 BQ20Z80A-V110 — SBS 1.1 compliant gas gauge enabled with Impedance Track™; technology for use with the bq29312A BQ27411-G1 — Pack-side Impedance Track™ fuel gauge | battery gas gauge BQ27421-G1 — System-side(tm) fuel gauge with integrated Sense Resistor | battery gas gauge BQ27425-G1 — System-side Impedance Track™; fuel gauge with direct battery connection | gas gauge battery BQ27425-G2A — System-side Impedance Track™; fuel gauge for LiCoO2 battery BQ27425-G2B — System-side Impedance Track™; fuel gauge LiMn2O4 battery BQ27426 — Single cell System-side battery fuel (gas) gauge w/Pre-programmed chemistry Profile BQ27427 — Single-cell battery fuel gauge with pre-programmed chemistry and integrated sense resistor BQ27441-G1 — System-side Impedance Track™ battery fuel (gas) gauge BQ27505-J2 — System-side Impedance Track™; fuel gauge with FW v2.15 BQ27505-J3 — System-side Impedance Track™; fuel gauge with FW v2.20 BQ27505-J4 — System-side Impedance Track™; fuel gauge with FW v2.24 BQ27505-J5 — System-side Impedance Track™; fuel gauge with FW v2.29 BQ27520-G4 — System side Impedance Track™ fuel gauge with integrated LDO. BQ27530-G1 — System-side Impedance-Track fuel (gas) gauge with direct battery connection BQ27531-G1 — Battery management unit Impedance Track™ fuel (gas) gauge for bq2419x charger controller BQ27532-G1 — Battery management unit Impedance Track™ fuel gauge for bq2425x charger BQ27545-G1 — Single cell, pack side, Impedance Track™ fuel gauge BQ27546-G1 — Single cell Impedance Track™ pack side fuel gauge with DSBGA package BQ27621-G1 — System-side fuel gauge with Dynamic Voltage Correlation, battery gas gauge BQ27741-G1 — Pack-side Impedance Track™(tm) fuel (gas) gauge with integrated protector BQ27742-G1 — Single cell Li-ion battery fuel gauge with integrated protection | battery gas gauge BQ3050 — SBS 1.1-compliant 2-s to 4-s battery gas gauge & protection BQ3055 — 2-series, 3-series, and 4-series Li-ion battery pack manager BQ3060 — SBS 1.1-compliant gas gauge and protector BQ30Z554-R1 — 2 series, 3 series, and 4 series Li-ion battery pack manager BQ34110 — Multi-chemistry high-cell Count battery fuel gauge with integrated rarely discharged module BQ34Z100 — 1-s to 16-s Impedance Track™ fuel gauge | battery gas gauge BQ34Z100-G1 — Multi-chemistry Impedance Track™ standalone fuel gauge | battery gas gauge BQ34Z100-R2 — Multichemistry Impedance Track™ stand-alone fuel gauge BQ34Z110 — Wide range fuel gauge with Impedance Track™; for lead acid batteries | battery gas gauge
Hardware development
Evaluation board
BQ2000EVM — Evaluation Module for Battery Charge Management IC BQ2022AEVM-001 — BQ2022A Evaluation Module BQ2026EVM — BQ2026 Evaluation Module BQ27411EVM-G1A — Pack-Side Impedance Track™ Fuel (Gas) Gauge Evaluation Module BQ27411EVM-G1C — BQ27411EVM-G1C Pack-Side Impedance Track™ Fuel (Gas) Gauge Evaluation Module BQ27421EVM-G1A — BQ27421EVM-G1A System-Side Battery Fuel (Gas) Gauge Evaluation Module Board BQ27421EVM-G1B — BQ27421EVM-G1B System-Side Battery Fuel (Gas) Gauge Evaluation Module BQ27425EVM-G2A — BQ27425EVM-G2A System-Side Impedance Track™ Fuel (Gas) Gauge Evaluation Module BQ27426EVM-738 — BQ27426 EVM for Impedance Track Fuel Gauge w/Easy to Use Pre-programmed Chemistry Profiles BQ27427EVM — BQ27427 evaluation module for Impedance Track™ battery gas gauge with integrated sense resistor BQ27441EVM-G1A — BQ27441 evaluation board  BQ27441EVM-G1B — BQ27441 evaluation board  BQ27510EVM — System-Side Single-Cell Impedance Track™ Technology Evaluation Module  | Battery Fuel Gauge BQ27520EVM — System-Side Impedance Track™ Battery Fuel Gauge Evaluation Module | Gas Gauge BQ27530EVM — BQ27530EVM System-Side Impedance-Track Fuel (Gas) Gauge Direct Battery Connection Evaluation Module BQ27531EVM — Battery Management Unit Impedance Track Fuel (Gas) Gauge Charger Controller Evaluation Module BQ27532EVM-656 — Battery Charging Solution Evaluation Module BQ27542EVM — Li-ion Battery Fuel Gauge Evaluation Module BQ27545EVM — BQ27545EVM Single Cell, Pack Side, Impedance Track Fuel Gauge Evaluation Module BQ27546EVM-702 — bq27546 Gas Gauge with Impedance Track™ Technology BQ27621EVM-G1 — System-Side Fuel (Gas) Gauge Dynamic Voltage Correlation Evaluation Module BQ27741EVM — BQ27741EVM Pack-Side Impedance Track Fuel (Gas) Gauge Integrated Protector Evaluation Module BQ27742EVM — bq27742-G1 Single Cell Li-ion Battery Fuel (Gas) Gauge Programmable Evaluation Module BQ27750EVM-837 — BQ27750 1-Cell Programmable Battery Manager Evaluation Module BQ3050EVM-001 — bq3050EVM SBS 1.1 Compliant Advanced Gas Gauge EVM BQ34110EVM-796 — bq34110 Multi-Chemistry CEDV Battery Gas Gauge for Rarely Discharged Applications Evaluation Module BQ34210IQ1EVM-826 — bq34210-Q1 Evaluation Module for System Side CEDV Fuel Gauge BQ34Z100EVM — Bq34z100EVM 1s to 16s Impedance Track Fuel Gauge Battery Evaluation Module | Gas Gauge Battery MKST-3P-ALT-EV2300 — MKS Technology alternative for EV2300 communications transceiver
Software
Support software
BQ20Z40-R1_BQEASY-SW — BQ20Z40-R1 bqEASY Software BQ20Z45-R1_BQEASY-SW — BQ20Z45-R1 bqEASY Software BQ20Z60-R1_BQEVSW-SW — BQ20Z60-R1 bqEASY Software BQ20Z65-R1_BQEVSW-SW — BQ20Z65-R1 bqEASY Software BQ3060-BQEVSW-SW — BQ3060 bqEVSW Software
Application software & framework
BQEVSW — BQ evaluation software (BQEVSW) v0.0.92 for BQ30Z554-R1
Download options
Reference designs

TIDA-00669 — 500mA Wireless Charger BoosterPack with Gauge Reference Design

The TIDA-00669 is a BoosterPack™ reference design that provides a wireless charger and battery management to power any TI LaunchPad™ (www.ti.com/launchpad). This is a highly-integrated power management reference design that is well-suited for low-power applications. The primary method of storage is (...)
Design guide: PDF
Schematic: PDF
Reference designs

TIDA-00712 — Smartwatch Battery Management Solution Reference Design

This reference design is for smartwatch battery management solution (BMS). It is suitable for low-power wearable devices like smartwatch applications. The design includes an ultra-low current 1 cell Li-ion linear charger; a highly integrated Qi-compliant wireless power receiver; a (...)
Design guide: PDF
Schematic: PDF
Reference designs

TIDA-00586 — Gauge Booster Pack Reference Design

The TIDA-00586 reference design is a gauge that has been designed as a booster pack to fit on the TI Launchpad development boards. The use of this this board for development will reduce the time spent in design and test of the bq27421 gauge IC. You can select any appropriate charger to charge your (...)
Design guide: PDF
Schematic: PDF
Reference designs

TIDA-00055 — Standalone Synchronous Switch-mode Li-Ion Charger with 2A FET Reference Design

This reference design is a solution for a Li-Ion charge management IC. It has a highly integrated battery charge IC utilizing synchronous switch mode power conversion for efficient and comprehensive charge control of a single cell Li-Ion battery. The solutionprovides a convenient method to evaluate (...)
Test report: PDF
Schematic: PDF
Reference designs

TIDA-00053 — 1A Single Cell Linear Charger for LiFePO4 Applications Reference Design

This reference design is designed to deliver up to 1 A of continuous current to the battery and/or system. It has a 4.9 VDC, 50 mA max internal LDO that can be used for USB applications or any other need. It uses the bq25070, a highly integrated LiFePO4 linear battery charger, in order to target (...)
Test report: PDF
Schematic: PDF
Reference designs

TIDA-00045 — Single-Chip Charge and Dynamic Power-Path Management IC Reference Design

This reference design is a Single-Chip Charge and Dynamic Power-Path Management IC solution. It is a complete bq24030 based circuit design and provides a convenient method to evaluate the operation and performance of the IC. The development solution includes a tested evaluation board; a user guide (...)
Test report: PDF
Schematic: PDF
Reference designs

TIDA-00044 — USB Li-Ion Battery Charger and Power-Path Management Reference Design

This reference design delivers up to 1000 mA of continuous current to the battery output when programmed with a resistor on the ISET pin and is programmed at the factory for ~540mA. The USB current limit modes are selected by the ISET2 pin and limits current to a maximum of 500 mA (logic high) or (...)
Test report: PDF
Schematic: PDF
Reference designs

TIDA-00042 — 1A Single-Input Single-Cell Li-Ion Battery Charger Reference Design

This reference design is targeted at space-limited portable applications. The devices in the design operate from either a USB port or AC adapter. The solution has a single power output that charges the battery. A system load can be placed in parallel with the battery as long as the average system (...)
Test report: PDF
Schematic: PDF
Reference designs

TIDA-00031 — System-Side ImpedanceTrack Fuel Gauge with Integrated Sense Resistor Reference Design

This reference design is a complete evaluation system solution for the bq27421. The solution includes one bq27421 circuit module with an integrated current-sense resistor. A separated orderable EV2300 or EV2400 PC interface board for gas gauge interface along with a PC USB cable, and (...)
Test report: PDF
Schematic: PDF
Package Pins CAD symbols, footprints & 3D models
DSBGA (YZF) 9 Ultra Librarian
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Ordering & quality

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