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January 2009 Rev 1 1/21

STC3100

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

■ 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.

MiniSO-8

(Plastic micropackage)

DFN8 3x3

(Plastic micropackage)

IO0

SDA

SCL

GND

VIN

ROSC

VCC

Pin connections

(top view)

www.st.com

Summary of content (21 pages)

PAGE 1
STC3100 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 MiniSO-8 (Plastic micropackage) DFN8 3x3 (Plastic micropackage) Applications ■ Cellular phones, PDA, MP3 players, cordles
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Block diagram 1 STC3100 Block diagram Figure 1. STC3100 internal block diagram 1.
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STC3100 2 Pin assignment Pin assignment Table 1.
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Absolute maximum ratings and operating conditions 3 Absolute maximum ratings and operating conditions Table 2. Absolute maximum ratings Symbol Vmax Parameter Maximum voltage on any pin Vio Voltage on I/O pins Tstg Storage temperature Tj ESD Table 3. Maximum junction temperature Electrostatic discharge (HBM human body model) Value Unit 7 V -0.
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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 100 uA Supply ICC Operating current consumption Average value over 4s Istby Current consumption in standby standby mode, inputs=0V 2 uA Ipdn Current consumption in power down VCC < UVLOth, inputs=0V 1 uA UVLOth Undervoltage threshold (VCC decreasing) 2.
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Electrical characteristics Table 4. STC3100 Electrical characteristics (2.7 V < VCC < 4.5 V, -20° C to 70° C) (continued) Symbol Parameter Conditions Min Typ Max Units 5 V Battery voltage and temperature a/d converter Vin_adc Input voltage range Vcc = 5 V LSB LSB value Voltage measurement Temperature measurement ADC_time AD conversion time (32,768 Hz clock) Volt_acc Battery voltage measurement accuracy 2.7 V
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STC3100 Typical performance curves 5 Typical performance curves Figure 2. Standby current vs. temperature Figure 3. 1.6 1.4 Current measurement accuracy vs. temperature 0.6 Vcc=4.5V Vgg=80mV 0.4 1.0 ADC_acc (%) Istby (uA) 1.2 0.8 0.6 0.2 0.0 -0.2 0.4 -0.4 0.2 0.0 -50 -25 0 25 50 75 100 -0.6 -50 125 -25 0 Temp (°C) Figure 4. 25 50 75 100 125 Temp (°C) Oscillator frequency accuracy vs. temperature Figure 5. 2.0 Voltage measurement accuracy vs. temperature 0.6 Vin=3.
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Application information 6 STC3100 Application information Figure 6. Example of an application schematic using the STC3100 Optional filter Rosc ROSC VCC C1 IO voltage R1 VIN C2 STC3100 SCL SDA CG Rcg GND IO0 AM00831 Table 5. 8/21 External components list Name Value Tolerance Comments Rcg 10 to 50 mΩ 1% Rosc 200 kΩ 0.
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STC3100 Functional description 7 Functional description 7.1 Gas gauge The gas gauge is used to monitor the available battery capacity. The voltage drop across the external sense resistor is integrated during a conversion period and input to a 12- to 14-bit AD converter. The output conversion is accumulated into a 28-bit accumulator. The system controller can control the gas gauge and read the data (upper 16 bits of the accumulator) through the I2C control registers.
PAGE 10
Functional description STC3100 The conversion cycle for n bit resolution is 2n clock cycles. Using the 32,768 Hz internal clock, the conversion cycle time is 125 to 500 ms for a 12- to 14-bit resolution. The LSB value is set by the internal gain and internal reference and is 11.77 uV at maximum resolutions. When using an external 30 milliOhms sense resistor, the 28-bit accumulator results in a capacity of approximately +/- 7300 mA.h.
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STC3100 7.5 Functional description Unique device ID The STC3100 provides a means to identify the battery pack or the subsystem. Each device has its own unique 8-byte ID made of an 8-bit part ID (value = 10h for the STC3100), a 48-bit random unique ID and an 8-bit CRC. The CRC-8 is calculated according to bytes REG_ID0 to REG_ID6 using the "x8 + x2 + x + 1" polynomial with a zero initial value.
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I2C interface STC3100 8 I2C interface 8.1 Read and write operations The interface is used to control and read the current accumulator and registers. It is compatible with the Philips I2C registered trademark (version 2.1). It is a slave serial interface with a serial data line (SDA) and a serial clock line (SCL). ● SCL: input clock used to shift data. ● SDA: input/output bidirectional data transfers. A filter rejects the potential spikes on the bus data line to preserve data integrity.
PAGE 13
STC3100 Figure 8. I2C interface Read operation Slave Master Start Device addr 7 bits W A Reg address 8 bits A Restart Device addr 7 bits R A Reg data 8 bits A Reg data 8 bits A A Stop Address n+2 Address n+1 Start bit = SDA falling when SCL = 1 Stop bit = SDA rising when SCL = 1 Restart bit = start after a start Acknowledge = SDA forced low during a SCL clock Reg data 8 bits AM00833 Figure 9.
PAGE 14
I2C interface 8.2 STC3100 Register map The register space provides 12 control registers, 8 read-only (factory OTP) registers for unique device ID and 32 read/write general-purpose RAM registers. Mapping of all registers is shown in Table 9. Detailed descriptions of registers 0 (REG_MODE) and 1 (REG_CTRL) are shown in Table 10 and Table 11. All registers are reset to default values at power-on or reset, and the PORDET bit in register REG_CTRL is used to indicate the occurrence of a power-on reset.
PAGE 15
STC3100 I2C interface Values held in consecutive registers (such as the charge value in the REG_CHARGE_LOW and REG_CHARGE_HIGH registers) must be read with a single I2C access to ensure data integrity. It is possible to read multiple values in one I2C access, all values will be consistent. The charge data is coded in 2’s complement format, and the LSB value is 6.70 uV.h. The battery current is coded in 2’s complement format, and the LSB value is 11.77 uV.
PAGE 16
Package information 9 STC3100 Package information In order to meet environmental requirements, ST offers these devices in different grades of ECOPACK® packages, depending on their level of environmental compliance. ECOPACK® specifications, grade definitions and product status are available at: www.st.com. ECOPACK® is an ST trademark.
PAGE 17
STC3100 9.1 Package information MiniSO-8 package information Figure 10. MiniSO-8 package mechanical drawing Table 12. Miniso-8 package mechanical data Dimensions Ref. Millimeters Min. Typ. Inches Max. Min. Typ. Max. A 1.10 0.043 A1 0.15 0.006 A2 0.75 b 0.95 0.030 0.22 0.40 0.009 0.016 c 0.08 0.23 0.003 0.009 D 2.80 3.00 3.20 0.110 0.118 0.126 E 4.65 4.90 5.15 0.183 0.193 0.203 E1 2.80 3.00 3.10 0.110 0.118 0.122 e L 0.85 0.65 0.40 0.60 0.033 0.
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Package information 9.2 STC3100 DFN8 package information Figure 11. DFN8 3x3x1.0 mm package mechanical drawing (pitch 0.5 mm) Table 13. DFN8 3x3x1.0 mm package mechanical data (pitch 0.5 mm) Dimensions Ref. A Millimeters Min. Typ. Max. Min. Typ. Max. 0.80 0.90 1.00 0.031 0.035 0.039 0.02 0.05 0.0008 0.0019 0.65 0.80 0.025 0.031 A1 A2 0.55 A3 0.021 0.20 0.008 b 0.18 0.25 0.30 0.007 0.010 0.012 D 2.85 3.00 3.15 0.112 0.118 0.124 D2 2.20 2.70 0.087 E 2.
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STC3100 10 Ordering information Ordering information Table 14.
PAGE 20
Revision history 11 STC3100 Revision history Table 15. 20/21 Document revision history Date Revision 27-Jan-2009 1 Changes Initial release.
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STC3100 Please Read Carefully: Information in this document is provided solely in connection with ST products. STMicroelectronics NV and its subsidiaries (“ST”) reserve the right to make changes, corrections, modifications or improvements, to this document, and the products and services described herein at any time, without notice. All ST products are sold pursuant to ST’s terms and conditions of sale.