ST AN3075 APPLICATION NOTE

AN3075

Application note

Demonstration board user guidelines for the

STC3100 battery monitor for gas gauge applications

Introduction

This application note describes the STEVAL-ISB009V1, a demonstration board specifically designed for the STC3100 integrated circuit.

The document provides:

● a brief description of the STC3100 device.

● a description of the demonstration board.

● a detailed bill of materials for the demonstration board.

● the layout of the demonstration board.

Figure 1. Demonstration board

October 2009 Doc ID 16365 Rev 1 1/9

www.st.com

About the STC3100 AN3075

1 About the STC3100

The STC3100 monitors the three main battery parameters: voltage, current and temperature, and includes a Coulomb counter to keep track of the charge/discharge status.

1.1 Features

● Accurate battery voltage measurement

● Coulomb counter to keep track of the battery’s state-of-charge

● Internal temperature sensor

● Internal or external 32 kHz timebase

● I2C interface for battery monitoring and device control

1.2 Performances:

● 0.5% battery voltage accuracy

● 1% Coulomb counter accuracy using an external RTC signal (3.5% using the internal

timebase).

● Low power consumption: 100 µA in operating conditions, 2 µA in standby mode.

1.3 Packages

● DFN8 3 x 3 (as used in the demonstration board)

● MiniSO-8

Refer to the STC3100 datasheet for more detailed information on the device.

2/9 Doc ID 16365 Rev 1

AN3075 About the STC3100

Figure 2. Typical application diagram for the STC3100

Battery State-of-charge

Remaining percentage

Remaining time

2:06

uC with

Gas Gauge

firmware

80 %

32768 Hz

clock

I2C bus

Battery data

Current

Voltage

Temperature

ROSC

SCL

SDA

0.32 A

3.71 V

STC3100

GND

27 ° C

VCC

VIN

IO0

Battery

Rcg

AM04578

Doc ID 16365 Rev 1 3/9

Demonstration board description AN3075

2 Demonstration board description

The STEVAL-ISB009V1 is a demonstration board designed to help you evaluate the performance of the STC3100.

Figure 3. Demonstration board schematic diagram

PT_VIN

IC1

PT_IO0

PT_ROSC

PT_SDA

PT_SCL

Rosc

200 K

STC3100

IO0

ROSC

SDA

SCL

VIN

VCC

GND

1 µF

PT_VCC

2.5 A

Rcg

33 m

P_GND

PT_CG

PT_GND

Table 1. Bill of materials

Part Part type Footprint Description

IC1 STC3100IQT DFN8 3x3

Battery monitoring integrated circuit from STMicroelectronics

Rosc 200 kΩ/0.1% 0603 Oscillator resistor

Rcg 33 mΩ/1% 0805 Shunt resistor

R2 0 Ω 0402 Strap

C1 1 µF/10 V/X7R 0402 Decoupling capacitor

C3 1 µF/10 V/X7R 0402 Optional filtering capacitor

AM04588

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AN3075 Demonstration board layout

3 Demonstration board layout

The printed circuit board of the demonstration board has the following characteristics.

● Board dimensions: 23 mm x 18 mm

● 2-layer PCB

● Thickness of PCB: 0.8 mm

● FR4 material

● Thickness of copper: 18 µm

Figure 4. Top view of demonstration board

Figure 5. Bottom view of demonstration board

Doc ID 16365 Rev 1 5/9

Demonstration board connections AN3075

4 Demonstration board connections

The STC3100 demonstration board can be simply connected to a battery and interfaced with a digital controller as shown in Figure 6.

Figure 6. Demonstration board connections with battery and microcontroller

IO voltage = 1.8 V (or 2.8 V, 3.3 V...)

10 K10 K

I2C master

SDA

SCL

AM04589

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AN3075 Conclusion

5 Conclusion

To order the board online, go to http://www.st.com/stonline/domains/buy/buy_dev.htm and use the order code STEVAL-ISB009V1.

Doc ID 16365 Rev 1 7/9

Revision history AN3075

6 Revision history

Table 2. Document revision history

Date Revision Changes

08-Oct-2009 1 Initial release.

8/9 Doc ID 16365 Rev 1

AN3075

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