UM1054

STC3105 overview

Doc ID 18463 Rev 1

3/10

1

STC3105 overview

The STC3105 monitors the voltage and current of the battery and includes a Coulomb

counter to keep track of the charge/discharge status. An alarm output signals a low State-

Of-Charge (SOC) condition and/or a low battery voltage. In addition, a relaxation register

starts to count when the gas gauge is in a specified light-load condition, indicating when an

OCV (Open Circuit Voltage) measurement should be made for SOC correction.

Features of the STC3105 include:

●

Accurate battery voltage measurement

●

Coulomb counter to keep track of the battery's SOC

●

Internal 32.768 kHz time base

●

Low-battery alarm output with programmable SOC and voltage thresholds

●

Relaxation timer to track the load condition (user programmable load current threshold)

●

Performance criteria of the device are:

●

0.5% battery voltage accuracy

●

1% Coulomb counter accuracy using an external sensing resistor

●

Low power consumption: 100 µA in active operating conditions, 50 µA in power saving

operating conditions, 2 µA in standby mode and 1 µA in power-down mode

The device is packaged in a TDFN8, 3 mm x 2 mm x 0.75 mm (pitch 0.65 mm) (as used in

the demonstration board).

Figure 2.

Typical application diagram for the STC3105

GND

SDA

SCL

ALM

VCC

VIN

CG

STC3105

Battery

Rcg

uC with

Gas Gauge

firmware

I2C bus

Battery State-of-charge

Battery data

80 %

Remaining percentage

Remaining time

2:06

0.32 A

Current

3.71 V

Voltage

AM045051v1