STC3105

STC3105 Battery monitor IC with alarm output for gas gauge applications 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 Applications ■ Mobile phones, multimedia players, digital cameras ■ Portable medical equipment Description The STC3105 battery monitor includes the hardware functions required to implement a lowcost gas gauge for battery monitoring. The STC3105 uses accurate measurements of the battery voltage to estimate a battery’s state-ofcharge (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. TDFN8 3x2 (Plastic micropackage) Pin connections (top view) ALM 1 SDA 2 SCL 3 GND 4 8 VIN 7 VCC 6 NC 5 CG September 2011 Doc ID 022198 Rev 1 1/23 www.st.com 23 Contents Contents STC3105 1 Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2 Pin assignment ...