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Battery monitor IC with alarm output for gas gauge applications

The STC3105 battery monitor includes the hardware functions required to implement a low-cost gas gauge for battery monitoring. The STC3105 uses accurate measurements of the battery voltage to estimate a battery’s state-of-charge (SOC). It uses a low cost sense resistor to precisely sense the charge or discharge states, detect light-load conditions without ambiguity for voltage measurements, and accurate SOC calculation. The coulomb counter method is used for SOC tracking in high-load conditions.

An alarm output signals a low SOC condition, and can also indicate low battery voltage. The alarm threshold levels are programmable.

The device is programmable through an I2C interface.

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Errata Sheet
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Key Features

  • 0.5% accuracy battery voltage monitoring
  • Low battery alarm output with programmable thresholds
  • Low power: 60 μA in power-saving mode, 2 μA max in standby mode
  • Ideal for implementation of robust gas gauge systems using open-circuit voltage and coulomb counter methods
  • Small 3x2 mm package

Design Resources


Technical Documentation

Product Specifications

Description Version Size
DS8643: Battery monitor IC with alarm output for gas gauge applications
1.1 321 KB

Application Notes

Description Version Size
AN3395: Sensing resistor selection and usage in STC310x battery monitoring applications
1.2 149 KB

User Manual

Description Version Size
UM1054: STEVAL-ISB013v1 demonstration board based on the STC3105 battery monitor IC with alarm output for gas gauge applications
1.2 305 KB
UM1481: STEVAL-ISB012V1 Li-Ion battery monitor and gas-gauge based on the STC3105
1.0 5,356 KB

Presentations & Training Material


Description Version Size
Health and Wellness Mobility Cloud computing
1,347 KB

Related Tools and Software

Related Tools and Software

Part Number Description
STEVAL-ISB012V1 Battery monitoring system demonstration board based on the STC3105
STEVAL-ISB013V1 Battery monitor demonstration board with alarm output for gas gauge applications based on the STC3105

Sample & Buy

Part Number Marketing StatusPackagePacking TypeOperating Temperature (min) Operating Temperature (max) Automotive GradeOrder From STUnit Price (US$)*
@ 1000
Distributor AvailabilityRoHS Compliance GradeDownload
Material Declaration**
STC3105IQTNRNDTDFN 3.0X2.0X0.75 8L PITCH 0.65Tape And Reel-4085_-1Distributor reported inventory date: 2016-02-09
Distributor NameRegionStockMin. order
ARROWOrder NowAMERICA28653000

(*) Suggested Resale Price per unit (USD) for BUDGETARY USE ONLY. For quotes, prices in local currency, please contact your local ST Sales Office or our Distributors
(**) The Material Declaration forms available on may be generic documents based on the most commonly used package within a package family. For this reason, they may not be 100% accurate for a specific device. Please contact our sales support for information on specific devices.
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