ST STC3100 User Manual

Battery monitor IC with Coulomb counter/gas gauge

Features

■ Battery voltage monitoring

■ Internal temperature sensor

■ Coulomb counter with 12/14-bit AD converter,

+/- 80 mV input voltage range

■ Internal or external 32768 Hz time base

■ I2C interface for gas gauge monitoring and

device control

■ 32-RAM bytes

■ 8-byte unique device ID

■ One general-purpose I/O

Applications

STC3100

MiniSO-8

(Plastic micropackage)

DFN8 3x3

(Plastic micropackage)

■ Cellular phones, PDA, MP3 players, cordless

phones

■ Digital cameras, USB appliances, Bluetooth

devices

Description

The STC3100 monitors the critical parameters of
a single-cell Li-Ion battery (voltage, temperature
and current) and includes hardware functions to
implement a gas gauge for battery charge
monitoring, based on a programmable 12- to
14-bit A/D converter. With a typical 30 milliOhms
external sense resistor, the battery current can be
up to 2.5 A and the accumulator system provides
a capacity up to +/-7000 mAh with a resolution of

0.2 mAh.

The device is programmable through the I2C
interface.

IO0

ROSC

SDA

SCL

Pin connections

(top view)

1
2

3

4

8

7

6

5

VIN

VCC
CG
GND

January 2009 Rev 1 1/21

www.st.com

21

Block diagram STC3100

1 Block diagram

Figure 1. STC3100 internal block diagram

VCC

SCL

SDA

Accumulators and

control registers

I2C interface

1.2 V

reference

AD converter

11 bits (unsigned)

AD converter

12 / 14 bits (signed)

General-purpose I/O line

RAM & ID registers

32 kHz

time base

GND

MUX

Oscillator ROSC

Temp sensor

VIN

CG+

CG-

CG

IO0

AM00830

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STC3100 Pin assignment

2 Pin assignment

Table 1. STC3100 pin description

Pin # Pin name Type Function

1 IO0 I/OD General-purpose I/O

2ROSC I_AD

3 SDA I/OD I2C serial data

4 SCL I_D I2C serial clock

5 GND Ground Analog and digital ground

6 CG I_A Gas gauge current sense input

7 VCC Supply Power supply

8 VIN I_A Battery voltage sense input

Note: I: input

O: output
OD: open drain
A: analog
D: digital

Oscillator bias resistor or external 32 kHz clock for gas
gauge

3/21

Absolute maximum ratings and operating conditions STC3100

3 Absolute maximum ratings and operating conditions

Table 2. Absolute maximum ratings

Symbol Parameter Value Unit

Vmax Maximum voltage on any pin 7 V

Vio Voltage on I/O pins -0.3 to 7 V

Tstg Storage temperature -55 to 150

Tj Maximum junction temperature 150

ESD Electrostatic discharge (HBM human body model) 2 kV

Table 3. Operating conditions

Symbol Parameter Value Unit

° C

° C

Vcc Operating supply voltage on V

CC

2.7 to 5.5 V

Vin Input voltage on Vin 0 to Vcc V

Vmin Minimum voltage on VCC for RAM content retention 2.0 V

Toper Operating free air temperature range -40 to 85

° C

4/21

STC3100 Electrical characteristics

4 Electrical characteristics

Table 4. Electrical characteristics (2.7 V < VCC < 4.5 V, -20° C to 70° C)

Symbol Parameter Conditions Min Typ Max Units

Supply

I

CC

Operating current consumption Average value over 4s 100 uA

Istby Current consumption in standby standby mode, inputs=0V 2 uA

Ipdn Current consumption in power down V

UVLOth Undervoltage threshold (V

< UVLOth, inputs=0V 1 uA

CC

decreasing) 2.5 2.6 2.7 V

CC

UVLOhyst Undervoltage threshold hysteresis 100 mV

POR Power-on reset threshold (V

decreasing) 2.0 V

CC

Gas gauge A/D converter

Vin_gg Input voltage range -80 +80 mV

Iin Input current for CG pin 500 nA

ADC_res AD converter granularity

12 bits
13 bits
14 bits

47.08

23.54

11.77

CG = 0V

ADC_offset AD converter offset

ADC_time AD conversion time (32768Hz clock)

ADC_acc AD converter gain accuracy at full scale

12 bits
13 bits
14 bits

12 bits
13 bits
14 bits

25° C
over temperature range

-2

-2

-3

125
250
500

2

LSB

2

LSB

3

LSB

0.51%

Fosc Internal time base frequency Rosc = 200 kΩ, 0.1% 32768 Hz

Osc_acc Internal time base accuracy

25° C, V

CC

=3.6V
over temperature and
voltage ranges

2

2.5%%

Fosc_ext External time base frequency range 30 70 kHz

uV
uV
uV

ms
ms
ms

%

Cur_res Current register LSB value 11.77 uV

Chg_res

Global_
CG_acc

Charge register LSB value
(32,768 Hz clock)

Gas gauge accuracy (not including the
external sense resistor tolerance)

=Cur_res*2^12*0.5/3600

Using internal time base
Using external time base

6.70 uV.h

3.51%
%

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Electrical characteristics STC3100

Table 4. Electrical characteristics (2.7 V < VCC < 4.5 V, -20° C to 70° C) (continued)

Symbol Parameter Conditions Min Typ Max Units

Battery voltage and temperature a/d converter

Vin_adc Input voltage range Vcc = 5 V 0 5 V

LSB LSB value

ADC_time AD conversion time (32,768 Hz clock) 250 ms

Volt_acc Battery voltage measurement accuracy 2.7 V<Vin<4.5 V, VCC=Vin -0.5 +0.5 %

Temp_acc Internal temperature sensor accuracy -3 +3 °C

Digital I/O pins (SCL, SDA, IO0)

Vih Input logic high 1.2 V

Vil Input logic low 0.35 V

Vol Output logic low (SDA, IO0) Iol = 4 mA 0.4 V

Voltage measurement
Temperature measurement

2.44

0.125

mV

°C

6/21

STC3100 Typical performance curves

5 Typical performance curves

Figure 2. Standby current vs. temperature Figure 3. Current measurement accuracy vs.

temperature

1.6

1.4

1.2

1.0

0.8

Istby (uA)

0.6

0.4

0.2

0.0

Vcc=4.5V

-50-250 255075100125

Temp (°C)

Figure 4. Oscillator frequency accuracy vs.

temperature

2.0

1.5

1.0

0.5

0.0

-0.5

Osc_acc (% )

-1.0

-1.5

-2.0

-50 -25 0 25 50 75 100 125

Temp (°C)

0.6

Vgg=80mV

0.4

0.2

0.0

ADC_acc (%)

-0.2

-0.4

-0.6

-50 -25 0 25 50 75 100 125

Temp (°C)

Figure 5. Voltage measurement accuracy vs.

temperature

0.6

Vin= 3.5V

0.4

0.2

0.0

Volt_acc ( %)

-0.2

-0.4

-0.6

-50-25 0 25 50 75100125

Temp (°C)

7/21