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bq27421-G1系统端Impedance Track?电量计，此电量计具有集成感测

电阻器

1特性3说明

?单节串联锂离子电池电量计德州仪器(TI)bq27421-G1电量计是一款可轻松配置

的微控制器外设，可针对单节锂离子电池提供系统端电–驻留在系统主板上

量计量。此器件对用户配置和系统微控制器固件开发–支持嵌入式或可拆除电池

的要求极低。

–由具有集成低压降稳压器(LDO)的电池直接供

电

此款电量计采用针对电量计量、已获专利的–低值集成感测电阻器

Impedance Track?算法，可提供诸如剩余电池容量（典型值7m?）

(mAh)、充电状态(%)和电池电压(mV)等信息。

?基于已获得专利的Impedance Track?技术，可轻

松配置电池电量计量通过bq27421-G1电量计进行电池电量监测只需将–用平滑滤波器报告剩余电量和充电状态(SOC)PACK+(P+)与PACK-(P-)连接至可拆卸电池组或嵌–针对电池老化、温度和速率变化进行自动调节入式电池电路。微型9球、1.62mm×1.58mm尺–电池运行状态（老化）估算寸、0.5mm间距的NanoFree?芯片级封装(DSBGA)?微控制器外设支持：是空间受限类应用的理想选择。

–400kHz I2C串口

器件信息(1)–可配置的SOC中断或

器件名称封装封装尺寸（标称值）电池低电量数字输出报警

bq27421-G1DSBGA(9) 1.62mm x1.58mm –内部温度传感器或

主机报告温度

2应用

?智能手机、功能型手机和平板电脑

?数码相机与视频摄像机

?手持式终端

?MP3或多媒体播放器(1)要了解所有可用封装，请见数据表末尾的可订购产品附录。

4简化电路原理图

bq27421-G1

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8.11I2C-Compatible Interface Communication Timing

1特性 (1)

Characteristics (7)

2应用 (1)

9Detailed Description (8)

3说明 (1)

9.1Overview (8)

4简化电路原理图 (1)

9.2Functional Block Diagram (8)

5修订历史记录 (2)

9.3Feature Description (8)

6Device Comparison Table (3)

9.4Device Functional Modes (9)

7Pin Configuration and Functions.........................39.5Programming. (9)

8Specifications.........................................................410Application and Implementation (13)

8.1Absolute Maximum Ratings......................................410.1Typical Application (13)

8.2Handling Ratings.......................................................411Power Supply Recommendation.. (14)

8.3Recommended Operating Conditions.......................411.1Power Supply Decoupling. (14)

8.4Thermal Information..................................................512Layout. (15)

8.5Supply Current (5)

12.1Layout Guidelines (15)

8.6Digital Input and Output DC Characteristics (5)

12.2Layout Example (15)

8.7LDO Regulator,Wake-up,and Auto-shutdown DC

13器件和文档支持 (16)

Characteristics (5)

13.1文档支持 (16)

8.8ADC(Temperature and Cell Measurement)

13.2商标 (16)

Characteristics (6)

13.3静电放电警告 (16)

8.9Integrating ADC(Coulomb Counter)Characteristics

...................................................................................613.4术语表. (16)

8.10Integrated Sense Resistor Characteristics.............614机械封装和可订购信息 (16)

5修订历史记录

Changes from Original(May2013)to Revision A Page ?已添加器件信息表 (1)

?Changed LiMnO4to LiCoO2 (3)

?Added bq27421-G1D device to data sheet (3)

?Updated BIN pin description (3)

?Updated GPOUT pin description (3)

?Added Handling Ratings (4)

?Added RemainingCapacityUnfiltered(),RemainingCapacityFiltered(),FullChargeCapacityUnfiltered(), FullChargeCapacityFlitered(),and StateOfChargeUnfiltered()to Table1 (9)

?Added EXIT_CFGUPDATE and EXIT_RESIM subcommands to Table2 (10)

?Changed Chem_ID description (10)

Pin A1Index Area

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6Device Comparison Table

PART NUMBER BATTERY TYPE CHEM_ID

(1)

PACKAGE

(2)

COMMUNICATION FORMAT

bq27421YZFR-G1A LiCoO 2

0x128(4.2V maximum charge)bq27421YZFT-G1A bq27421YZFR-G1B LiCoO 2

0x312CSP-9

I 2C

(4.3to 4.35V maximum charge)bq27421YZFT-G1B bq27421YZFR-G1D LiCoO 2

0x3142

(4.3to 4.4V maximum charge)

bq27421YZFT-G1D (1)See the CHEM_ID subcommand to confirm the battery chemistry type.

(2)

For the most current package and ordering information see the Package Option Addendum at the end of this document;or,see the TI website at https://www.wendangku.net/doc/131028458.html, .

7Pin Configuration and Functions

Pin Functions

TYPE (1)DESCRIPTION

NAME NUMBER

LDO regulator input,battery voltage input,and coulomb counter input typically connected to the BAT

PI,AI

PACK+terminal.

Battery insertion detection input.If Operation Configuration bit [BIE]=1(default),a logic low on the pin is detected as battery insertion.For a removable pack,the BIN pin can be connected to V SS through a pulldown resistor on the pack,typically the 10-k Ωthermistor;the system board should use a 1.8-M Ωpullup resistor to V DD to ensure the BIN pin is high when a battery is removed.If the

battery is embedded in the system,it is recommended to leave [BIE]=1and use a 10-k Ωpulldown BIN B1DI

resistor from BIN to V SS .If [BIE]=0,then the host must inform the gauge of battery insertion and removal with the BAT_INSERT and BAT_REMOVE subcommands.A 10-k Ωpulldown resistor should be placed between BIN and V SS ,even if this pin is unused.

NOTE:The BIN pin must not be shorted directly to V CC or V SS and any pullup resistor on the BIN pin must be connected only to V DD and not an external voltage rail.

This open-drain output can be configured to indicate BAT_LOW when the Operation Configuration [BATLOWEN]bit is set.By default [BATLOWEN]is cleared and this pin performs an interrupt GPOUT A1DO

function (SOC_INT)by pulsing for specific events,such as a change in State of Charge.Signal polarity for these functions is controlled by the [GPIOPOL]configuration bit.This pin should not be left floating,even if unused,so a 10-k Ωpullup resistor is recommended.

(1)IO =Digital input-output,AI =Analog input,P =Power connection

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Pin Functions(continued)

TYPE(1)DESCRIPTION

NAME NUMBER

SCL A3DIO Slave I2C serial bus for communication with system(Master).Open-drain https://www.wendangku.net/doc/131028458.html,e with external

10-k?pullup resistors(typical)for each pin.If the external pullup resistors will be disconnected from

these pins during normal operation,recommend using external1-M?pulldown resistors to V SS at SDA A2DIO

each pin to avoid floating inputs.

Integrated high-side sense resistor and coulomb counter input typically connected to system power SRX C2AI

rail VSYS.

1.8-V Regulator Output.Decouple with0.47-μF ceramic capacitor to V SS.This pin is not intended to V DD B3PO

provide power for other devices in the system.

Ground pins.The center pin B2is the actual device ground pin while pin C1is floating internally and

therefore C1may be used as a bridge to connect to the board ground plane without requiring a via

V SS B2,C1PI

under the device package.Recommend routing the center pin B2to the corner pin C1using a top-

layer metal trace on the board.Then route the corner pin C1to the board ground plane.

8Specifications

8.1Absolute Maximum Ratings

over operating free-air temperature range(unless otherwise noted)(1)

PARAMETER MIN MAX UNIT

V BAT BAT pin input voltage range–0.36V

V SRX SRX pin input voltage range V BAT–0.3V BAT+0.3V

V DD V DD pin supply voltage range(LDO output)–0.32V

V IOD Open-drain IO pins(SDA,SCL,GPOUT)–0.36V

V IOPP Push-pull IO pins(BIN)–0.3V DD+0.3V

T A Operating free-air temperature range–4085°C (1)Stresses beyond those listed under"absolute maximum ratings"may cause permanent damage to the device.These are stress ratings

only,and functional operation of the device at these or any other conditions beyond those indicated under"recommended operating conditions"is not implied.Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.

8.2Handling Ratings

MIN MAX UNIT

T stg Storage temperature range–65150°C

Human body model(HBM),per ANSI/ESDA/JEDEC JS-001,–1.5 1.5

all pins(1)

V(ESD)Electrostatic discharge

Charged device model(CDM),per JEDEC specification–250250

JESD22-C101,all pins(2)

(1)JEDEC document JEP155states that500-V HBM allows safe manufacturing with a standard ESD control process.

(2)JEDEC document JEP157states that250-V CDM allows safe manufacturing with a standard ESD control process.

8.3Recommended Operating Conditions

T A=30°C and V REGIN=V BAT=3.6V(unless otherwise noted)

PARAMETER TEST CONDITIONS MIN TYP MAX UNIT

External input capacitor for internal Nominal capacitor values specified.

C BAT(1)0.1μF

LDO between BAT and V SS Recommend a5%ceramic X5R-

type capacitor located close to the

External output capacitor for internal

C LDO18(1)0.47μF

device.

LDO between V DD and V SS

External pull-up voltage for open-

V PU(1) 1.62 3.6V drain pins(SDA,SCL,GPOUT)

(1)Specified by design.Not production tested.

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8.4Thermal Information

over operating free-air temperature range(unless otherwise noted)

bq27421-G1

THERMAL METRIC(1)UNIT

YZF(9PINS)

RθJA Junction-to-ambient thermal resistance107.8

RθJCtop Junction-to-case(top)thermal resistance0.7

RθJB Junction-to-board thermal resistance60.4

°C/W

ψJT Junction-to-top characterization parameter 3.5

ψJB Junction-to-board characterization parameter60.4

RθJCbot Junction-to-case(bottom)thermal resistance NA

(1)For more information about traditional and new thermal metrics,see the IC Package Thermal Metrics application report,SPRA953

8.5Supply Current

T A=30°C and V REGIN=V BAT=3.6V(unless otherwise noted)

PARAMETER TEST CONDITIONS MIN TYP MAX UNIT

I CC(1)NORMAL mode current I LOAD>Sleep Current(2)93μA

I SLP(1)SLEEP mode current I LOAD

I HIB(1)HIBERNATE mode current I LOAD

Fuel gauge in host commanded

I SD(1)SHUTDOWN mode current SHUTDOWN mode0.6μA

(LDO regulator output disabled)

(1)Specified by design.Not production tested.

(2)Wake Comparator Disabled.

8.6Digital Input and Output DC Characteristics

T A=–40°C to85°C,typical values at T A=30°C and V REGIN=3.6V(unless otherwise noted)

PARAMETER TEST CONDITIONS MIN TYP MAX UNIT

V IH(OD)Input voltage,high(2)External pullup resistor to V PU V PU×0.7V

V IL Input voltage,low(2)(3)0.6V

V OL Output voltage,low(2)0.6V

I OH Output source current,high(2)(3)0.5mA

I OL(OD)Output sink current,low(2)–3mA

C IN(1)Input capacitance(2)(3)5pF

Input leakage current

0.1

(SCL,SDA,BIN)

I lkgμA

Input leakage current(GPOUT)1

(1)Specified by design.Not production tested.

(2)Open Drain pins:(SCL,SDA,GPOUT)

(3)Push-pull pin:(BIN)

8.7LDO Regulator,Wake-up,and Auto-shutdown DC Characteristics

T A=–40°C to85°C,typical values at T A=30°C and V REGIN=3.6V(unless otherwise noted)

PARAMETER TEST CONDITIONS MIN TYP MAX UNIT

V BAT BAT pin regulator input 2.45 4.5V

V DD Regulator output voltage 1.8V

V BAT undervoltage lockout

UVLO IT+2V LDO wake-up rising threshold

V BAT undervoltage lockout

UVLO IT- 1.95V LDO auto-shutdown falling threshold

(1)Specified by design.Not production tested.

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8.8ADC(Temperature and Cell Measurement)Characteristics

T A=–40°C to85°C;typical values at T A=30°C and V REGIN=3.6V(unless otherwise noted)

PARAMETER TEST CONDITIONS MIN TYP MAX UNIT

V IN(BAT)BAT pin voltage measurement Voltage divider enabled. 2.45 4.5V range.

t ADC_CONV Conversion time125ms Effective resolution15bits (1)Specified by design.Not tested in production.

8.9Integrating ADC(Coulomb Counter)Characteristics

T A=–40°C to85°C;typical values at T A=30°C and V REGIN=3.6V(unless otherwise noted)

PARAMETER TEST CONDITIONS MIN TYP MAX UNIT

V SR Input voltage range from BAT to BAT±25mV SRX pins

t SR_CONV Conversion time Single conversion1s Effective Resolution Single conversion16bits (1)Assured by design.Not tested in production.

8.10Integrated Sense Resistor Characteristics

T A=–40°C to85°C;typical values at T A=30°C and V REGIN=3.6V(unless otherwise noted)

PARAMETER TEST CONDITIONS MIN TYP MAX UNIT SRX RES(2)Resistance of Integrated Sense T A=30°C7m?Resistor from SRX to V SS.

I SRX(1)Recommended Sense Resistor input Long term RMS,average device2000mA

current.utilization

Peak RMS current,10%device2500mA

utilization(3)

Peak pulsed current,250ms3500mA

maximum,1%device utilization(3)

(1)Specified by design.Not tested in production.

(2)Firmware compensation applied for temperature coefficient of resistor.

(3)Device utilization is the long term usage profile at a specific condition compared to the average condition.

t SU(STA) SCL

SDA

t w(H)t

w(L)

t f t

r t(BUF) t r

t d(STA)

REPEATED START t h(DAT)t su(DAT)

t f t su(STOP)

STOP START

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8.11I2C-Compatible Interface Communication Timing Characteristics

T A=–40°C to85°C;typical values at T A=30°C and V REGIN=3.6V(unless otherwise noted)

PARAMETER TEST CONDITIONS MIN TYP MAX UNIT Standard Mode(100kHz)

t d(STA)Start to first falling edge of SCL4μs

t w(L)SCL pulse duration(low) 4.7μs

t w(H)SCL pulse duration(high)4μs

t su(STA)Setup for repeated start 4.7μs

t su(DAT)Data setup time Host drives SDA250ns

t h(DAT)Data hold time Host drives SDA0ns

t su(STOP)Setup time for stop4μs

t(BUF)Bus free time between stop and start Includes Command Waiting Time66μs

t f SCL or SDA fall time(1)300ns

t r SCL or SDA rise time(1)300ns

f SCL Clock frequency(2)100kHz Fast Mode(400kHz)

t d(STA)Start to first falling edge of SCL600ns

t w(L)SCL pulse duration(low)1300ns

t w(H)SCL pulse duration(high)600ns

t su(STA)Setup for repeated start600ns

t su(DAT)Data setup time Host drives SDA100ns

t h(DAT)Data hold time Host drives SDA0ns

t su(STOP)Setup time for stop600ns

t(BUF)Bus free time between stop and start Includes Command Waiting Time66μs

t f SCL or SDA fall time(1)300ns

t r SCL or SDA rise time(1)300ns

f SCL Clock frequency(2)400kHz

(1)Specified by design.Not production tested.

(2)If the clock frequency(f SCL)is>100kHz,use1-byte write commands for proper operation.All other transactions types are supported at

400kHz.(See and)

Figure1.I2C-Compatible Interface Timing Diagrams

I 2C Bus

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9Detailed Description

9.1Overview

The fuel gauge accurately predicts the battery capacity and other operational characteristics of a single Li-based rechargeable cell.It can be interrogated by a system processor to provide cell information,such as state-of-charge (SOC).

NOTE

The following formatting conventions are used in this document:

Commands :italics with parentheses()and no breaking spaces,for example,Control()Data Flash :italics ,bold ,and breaking spaces,for example,Design Capacity Register bits and flags :italics with brackets [],for example,[TDA]Data Flash bits :italics ,bold ,and brackets [],for example,[LED1]Modes and states :ALL CAPITALS,for example,UNSEALED mode

9.2Functional Block Diagram

9.3Feature Description

Information is accessed through a series of commands,called Standard Commands .Further capabilities are provided by the additional Extended Commands set.Both sets of commands,indicated by the general format Command(),are used to read and write information contained within the control and status registers,as well as its data https://www.wendangku.net/doc/131028458.html,mands are sent from system to gauge using the I 2C serial communications engine,and can be executed during application development,system manufacture,or end-equipment operation.

The key to the high-accuracy gas gauging prediction is Texas Instruments proprietary Impedance Track?algorithm.This algorithm uses cell measurements,characteristics,and properties to create state-of-charge predictions that can achieve high-accuracy across a wide variety of operating conditions and over the lifetime of the battery.

The fuel gauge measures the charging and discharging of the battery by monitoring the voltage across a small-value sense resistor.When a cell is attached to the fuel gauge,cell impedance is computed,based on cell current,cell open-circuit voltage (OCV),and cell voltage under loading conditions.

The fuel gauge uses an integrated temperature sensor for estimating cell temperature.Alternatively,the host processor can provide temperature data for the fuel gauge.

More details are found in the bq27421-G1Technical Reference Manual (SLUUAC5).

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9.4Device Functional Modes

To minimize power consumption,the fuel gauge has several power modes:INITIALIZATION,NORMAL,SLEEP, HIBERNATE,and SHUTDOWN.The fuel gauge passes automatically between these modes,depending upon the occurrence of specific events,though a system processor can initiate some of these modes directly.More details are found in the bq27421-G1Technical Reference Manual(SLUUAC5).

9.5Programming

9.5.1Standard Data Commands

The fuel gauge uses a series of2-byte standard commands to enable system reading and writing of battery information.Each standard command has an associated command-code pair,as indicated in Table1.Because each command consists of two bytes of data,two consecutive I2C transmissions must be executed both to initiate the command function,and to read or write the corresponding two bytes of data.Additional details are found in the bq27421-G1Technical Reference Manual(SLUUAC5).

Table1.Standard Commands

NAME COMMAND UNIT SEALED ACCESS

CODE

Control()CNTL0x00and0x01NA RW Temperature()TEMP0x02and0x030.1°K RW

Voltage()VOLT0x04and0x05mV R

Flags()FLAGS0x06and0x07NA R NominalAvailableCapacity()0x08and0x09mAh R FullAvailableCapacity()0x0A and0x0B mAh R RemainingCapacity()RM0x0C and0x0D mAh R FullChargeCapacity()FCC0x0E and0x0F mAh R AverageCurrent()0x10and0x11mA R StandbyCurrent()0x12and0x13mA R MaxLoadCurrent()0x14and0x15mA R AveragePower()0x18and0x19mW R StateOfCharge()SOC0x1C and0x1D%R InternalTemperature()0x1E and0x1F0.1°K R StateOfHealth()SOH0x20and0x21num/%R RemainingCapacityUnfiltered()0x28and0x29mAh R RemainingCapacityFiltered()0x2A and0x2B mAh R FullChargeCapacityUnfiltered()0x2C and0x2D mAh R FullChargeCapacityFlitered()0x2E and0x2F mAh R StateOfChargeUnfiltered()0x30and0x31%R

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Issuing a Control()command requires a subsequent2-byte subcommand.These additional bytes specify the particular control function desired.The Control()command allows the system to control specific features of the fuel gauge during normal operation and additional features when the device is in different access modes,as described in Table2.Additional details are found in the bq27421-G1Technical Reference Manual(SLUUAC5).

Table2.Control()Subcommands

CNTL FUNCTION CNTL DATA SEALED ACCESS DESCRIPTION

CONTROL_STATUS0x0000Yes Reports the status of device.

DEVICE_TYPE0x0001Yes Reports the device type(0x0421).

FW_VERSION0x0002Yes Reports the firmware version of the device.

DM_CODE0x0004Yes Reports the Data Memory Code number stored in NVM.

PREV_MACWRITE0x0007Yes Returns previous MAC command code.

CHEM_ID0x0008Yes Reports the chemical identifier of the battery profile used by the fuel

gauge.

BAT_INSERT0x000C Yes Forces the Flags()[BAT_DET]bit set when the OpConfig[BIE]bit is0. BAT_REMOVE0x000D Yes Forces the Flags()[BAT_DET]bit clear when the OpConfig[BIE]bit is

SET_HIBERNATE0x0011Yes Forces CONTROL_STATUS[HIBERNATE]to1.

CLEAR_HIBERNATE0x0012Yes Forces CONTROL_STATUS[HIBERNATE]to0.

SET_CFGUPDATE0x0013No Force CONTROL_STATUS[CFGUPMODE]to1and gauge enters

CONFIG UPDATE mode.

SHUTDOWN_ENABLE0x001B No Enables device SHUTDOWN mode.

SHUTDOWN0x001C No Commands the device to enter SHUTDOWN mode.

SEALED0x0020No Places the device in SEALED access mode.

TOGGLE_GPOUT0x0023Yes Commands the device to toggle the GPOUT pin for1ms.

RESET0x0041No Performs a full device reset.

SOFT_RESET0x0042No Gauge exits CONFIG UPDATE mode.

EXIT_CFGUPDATE0x0043No Exits CONFIG UPDATE mode without an OCV measurement and

without resimulating to update StateOfCharge().

EXIT_RESIM0x0044No Exits CONFIG UPDATE mode without an OCV measurement and

resimulates with the updated configuration data to update

StateOfCharge().

9.5.3Extended Data Commands

Extended data commands offer additional functionality beyond the standard set of commands.They are used in the same manner;however,unlike standard commands,extended commands are not limited to2-byte words. The number of command bytes for a given extended command ranges in size from single to multiple bytes,as specified in Table3.

Table3.Extended Commands

Name Command Code Unit SEALED UNSEALED

Access(1)(2)Access(1)(2) OpConfig()0x3A and0x3B NA R R DesignCapacity()0x3C and0x3D mAh R R

DataClass()(2)0x3E NA NA RW DataBlock()(2)0x3F NA RW RW BlockData()0x40through0x5F NA R RW BlockDataCheckSum()0x60NA RW RW BlockDataControl()0x61NA NA RW

Reserved0x62through0x7F NA R R

(1)SEALED and UNSEALED states are entered via commands to Control()0x00and0x01

(2)In SEALED mode,data cannot be accessed through commands0x3E and0x3F.

(a)1-byte write

(b)

quick read

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9.5.4Communications 9.5.4.1I 2C Interface

The fuel gauge supports the standard I 2C read,incremental read,quick read,one-byte write,and incremental write functions.The 7-bit device address (ADDR)is the most significant 7bits of the hex address and is fixed as 1010101.The first 8bits of the I 2C protocol are,therefore,0xAA or 0xAB for write or read,respectively.

The quick read returns data at the address indicated by the address pointer.The address pointer,a register internal to the I 2C communication engine,increments whenever data is acknowledged by the fuel gauge or the I 2C master.“Quick writes”function in the same manner and are a convenient means of sending multiple bytes to consecutive command locations (such as two-byte commands that require two bytes of data).The following command sequences are not supported:

Attempt to write a read-only address (NACK after data sent by master):

Attempt to read an address above 0x6B (NACK command):

9.5.4.2I 2C Time Out

The I 2C engine releases both SDA and SCL if the I 2C bus is held low for 2seconds.If the fuel gauge is holding the lines,releasing them frees them for the master to drive the lines.If an external condition is holding either of the lines low,the I 2C engine enters the low-power sleep mode.

A A S A A A S A bq27421-G1

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9.5.4.3I 2C Command Waiting Time

To ensure proper operation at 400kHz,a t (BUF)≥66μs bus-free waiting time must be inserted between all packets addressed to the fuel gauge.In addition,if the SCL clock frequency (f SCL )is >100kHz,use individual 1-byte write commands for proper data flow control.The following diagram shows the standard waiting time required between issuing the control subcommand the reading the status result.For read-write standard command,a minimum of 2seconds is required to get the result updated.For read-only standard commands,there is no waiting time required,but the host must not issue any standard command more than two times per second.Otherwise,the gauge could result in a reset issue due to the expiration of the watchdog timer.

9.5.4.4I 2C Clock Stretching

A clock stretch can occur during all modes of fuel gauge operation.In SLEEP and HIBERNATE modes,a short ≤100-μs clock stretch occurs on all I 2C traffic as the device must wake-up to process the packet.In the other modes (INITIALIZATION,NORMAL)a ≤4-ms clock stretching period may occur within packets addressed for the fuel gauge as the I 2C interface performs normal data flow control.

bq27421-G1 https://www.wendangku.net/doc/131028458.html, ZHCSB26A–MAY2013–REVISED AUGUST2014

10Application and Implementation

10.1Typical Application

bq27421-G1

ZHCSB26A–MAY2013–REVISED https://www.wendangku.net/doc/131028458.html, 11Power Supply Recommendation

11.1Power Supply Decoupling

The battery connection on the BAT pin is used for two purposes:

?To supply power to the fuel gauge

?As an input for voltage measurement of the battery

If the connection between the battery pack and the BAT pin has the potential to pick up noise,then a1.0-μF capacitor is recommended between the BAT pin and V SS.The capacitor should be placed close to the gauge IC and have short traces to both the V DD pin and V SS.

The fuel gauge has an integrated LDO with an output on the V DD pin of approximately1.8V.A capacitor of value at least0.47μF should be connected between the V DD pin and V SS.The capacitor should be placed close to the gauge IC and have short traces to both the V DD pin and V SS.

bq27421-G1 https://www.wendangku.net/doc/131028458.html, ZHCSB26A–MAY2013–REVISED AUGUST2014

12Layout

12.1Layout Guidelines

?A capacitor,of value at least0.47μF,is connected between the V DD pin and V SS.The capacitor should be placed close to the gauge IC and have short traces to both the V DD pin and V SS.

?It is recommend to have a capacitor,at least1.0μF,connect between the BAT pin and V SS if the connection between the battery pack and the gauge BAT pin has the potential to pick up noise.The capacitor should be placed close to the gauge IC and have short traces to both the V DD pin and V SS.

?If the external pullup resistors on the SCL and SDA lines will be disconnected from the host during low-power operation,it is recommend to use external1-MΩpulldown resistors to V SS to avoid floating inputs to the I2C engine.

?The value of the SCL and SDA pullup resistors should take into consideration the pullup voltage and the bus capacitance.Some recommended values,assuming a bus capacitance of10pF,can be seen in Table4.

Table4.Recommended Values for SCL and SDA Pullup Resistors VPU 1.8V 3.3V

Range Typical Range Typical R PU

400Ω≤R PU≤37.6kΩ10kΩ900Ω≤R PU≤29.2kΩ 5.1kΩ

?If the GPOUT pin is not used by the host,the pin should still be pulled up to V DD with a4.7-kΩor10-kΩresistor.

?If the battery pack thermistor is not connected to the BIN pin,the BIN pin should be pulled down to V SS with a 10-kΩresistor.

?The BIN pin should not be shorted directly to V DD or V SS.

?The actual device ground is the center pin(B2).The C1pin is floating internally and can be used as a bridge to connect the board ground plane to the device ground(B2).

12.2Layout Example

Figure2.bq27421-G1Board Layout

bq27421-G1

ZHCSB26A–MAY2013–REVISED https://www.wendangku.net/doc/131028458.html, 13器件和文档支持

13.1文档支持

13.1.1德州仪器(TI)相关文档

如需以下任何TI文档的副本，请致电(800)477-8924联系德州仪器(TI)文献咨询中心或致电(972)644-5580联系产品信息中心(PIC)。订购时，可通过文档标题或文献编号识别文档。也可通过TI网站获取更新版本的文档，网址：https://www.wendangku.net/doc/131028458.html,。

1.《bq27421-G1技术参考用户指南》(SLUUAC5)

2.《bq27421EVM：单节电池技术用户指南》(SLUUA63)

3.《bq27421-G1快速入门指南》(SLUUAH7)

4.《单节电池电量监测计电路设计》(SLUA456)

5.《bq27500和bq27501主要设计注意事项》(SLUA439)

6.《单节电池Impedance Track印刷电路板布局布线指南》(SLUA457)

7.《手持式电池电子产品中的ESD和RF迁移》(SLUA460)

13.2商标

Impedance Track,NanoFree are trademarks of Texas Instruments.

All other trademarks are the property of their respective owners.

13.3静电放电警告

ESD可能会损坏该集成电路。德州仪器(TI)建议通过适当的预防措施处理所有集成电路。如果不遵守正确的处理措施和安装程序,可能会损坏集成电路。

ESD的损坏小至导致微小的性能降级,大至整个器件故障。精密的集成电路可能更容易受到损坏,这是因为非常细微的参数更改都可能会导致器件与其发布的规格不相符。

13.4术语表

SLYZ022—TI术语表。

这份术语表列出并解释术语、首字母缩略词和定义。

14机械封装和可订购信息

以下页中包括机械封装和可订购信息。这些信息是针对指定器件可提供的最新数据。这些数据会在无通知且不对本文档进行修订的情况下发生改变。欲获得该数据表的浏览器版本，请查阅左侧的导航栏。

重要声明

德州仪器(TI)及其下属子公司有权根据JESD46最新标准,对所提供的产品和服务进行更正、修改、增强、改进或其它更改，并有权根据JESD48最新标准中止提供任何产品和服务。客户在下订单前应获取最新的相关信息,并验证这些信息是否完整且是最新的。所有产品的销售都遵循在订单确认时所提供的TI销售条款与条件。

TI保证其所销售的组件的性能符合产品销售时TI半导体产品销售条件与条款的适用规范。仅在TI保证的范围内，且TI认为有必要时才会使用测试或其它质量控制技术。除非适用法律做出了硬性规定，否则没有必要对每种组件的所有参数进行测试。

TI对应用帮助或客户产品设计不承担任何义务。客户应对其使用TI组件的产品和应用自行负责。为尽量减小与客户产品和应用相关的风险，客户应提供充分的设计与操作安全措施。

TI不对任何TI专利权、版权、屏蔽作品权或其它与使用了TI组件或服务的组合设备、机器或流程相关的TI知识产权中授予的直接或隐含权限作出任何保证或解释。TI所发布的与第三方产品或服务有关的信息，不能构成从TI获得使用这些产品或服务的许可、授权、或认可。使用此类信息可能需要获得第三方的专利权或其它知识产权方面的许可，或是TI的专利权或其它知识产权方面的许可。

对于TI的产品手册或数据表中TI信息的重要部分，仅在没有对内容进行任何篡改且带有相关授权、条件、限制和声明的情况下才允许进行复制。TI对此类篡改过的文件不承担任何责任或义务。复制第三方的信息可能需要服从额外的限制条件。

在转售TI组件或服务时，如果对该组件或服务参数的陈述与TI标明的参数相比存在差异或虚假成分，则会失去相关TI组件或服务的所有明示或暗示授权，且这是不正当的、欺诈性商业行为。TI对任何此类虚假陈述均不承担任何责任或义务。

客户认可并同意，尽管任何应用相关信息或支持仍可能由TI提供，但他们将独力负责满足与其产品及在其应用中使用TI产品相关的所有法律、法规和安全相关要求。客户声明并同意，他们具备制定与实施安全措施所需的全部专业技术和知识，可预见故障的危险后果、监测故障及其后果、降低有可能造成人身伤害的故障的发生机率并采取适当的补救措施。客户将全额赔偿因在此类安全关键应用中使用任何TI组件而对TI及其代理造成的任何损失。

在某些场合中，为了推进安全相关应用有可能对TI组件进行特别的促销。TI的目标是利用此类组件帮助客户设计和创立其特有的可满足适用的功能安全性标准和要求的终端产品解决方案。尽管如此，此类组件仍然服从这些条款。

TI组件未获得用于FDA Class III（或类似的生命攸关医疗设备）的授权许可，除非各方授权官员已经达成了专门管控此类使用的特别协议。只有那些TI特别注明属于军用等级或“增强型塑料”的TI组件才是设计或专门用于军事/航空应用或环境的。购买者认可并同意，对并非指定面向军事或航空航天用途的TI组件进行军事或航空航天方面的应用，其风险由客户单独承担，并且由客户独力负责满足与此类使用相关的所有法律和法规要求。

TI已明确指定符合ISO/TS16949要求的产品，这些产品主要用于汽车。在任何情况下，因使用非指定产品而无法达到ISO/TS16949要

求，TI不承担任何责任。

产品应用

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PACKAGING INFORMATION

(1) The marketing status values are defined as follows:

ACTIVE: Product device recommended for new designs.

LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.

NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.

PREVIEW: Device has been announced but is not in production. Samples may or may not be available.

OBSOLETE: TI has discontinued the production of the device.

(2) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check https://www.wendangku.net/doc/131028458.html,/productcontent for the latest availability information and additional product content details.

TBD: The Pb-Free/Green conversion plan has not been defined.

Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes.

Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above.

Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material)

(3) MSL, Peak Temp. - The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature.

(4) There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device.

(5) Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation of the previous line and the two combined represent the entire Device Marking for that device.

Addendum-Page 1

(6) Lead/Ball Finish - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead/Ball Finish values may wrap to two lines if the finish value exceeds the maximum column width.

Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals. TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release.

In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis.

Addendum-Page 2

TAPE AND REEL INFORMATION

*All dimensions are nominal

Device

Package Type Package Drawing Pins SPQ

Reel Diameter (mm)Reel Width W1(mm)A0(mm)B0(mm)K0(mm)P1(mm)W (mm)Pin1Quadrant BQ27421YZFR-G1A DSBGA YZF 93000180.08.4 1.78 1.780.69 4.08.0Q1BQ27421YZFR-G1B DSBGA YZF 93000180.08.4 1.78 1.780.69 4.08.0Q1BQ27421YZFR-G1D DSBGA YZF 93000180.08.4 1.78 1.780.69 4.08.0Q1BQ27421YZFT-G1A DSBGA YZF 9250180.08.4 1.78 1.780.69 4.08.0Q1BQ27421YZFT-G1B

DSBGA

YZF

250

180.0

8.4

1.78

0.69

4.0

8.0