BQ2040SN-C408中文资料应用文章市场行情现货热卖使用介绍-中国IC网-芯三七

bq2040

Gas Gauge IC With SMBus Interface

The bq2040 estimates battery self-

discharge based on an internal

Features

General Description

timer and temperature sensor and

The bq2040 Gas Gauge IC With

user-programmable rate informa-

SMBus Interface is intended for

tion stored in external EEPROM.

battery-pack or in-system installa-

The bq2040 also automatically re-

tion to maintain an accurate record

calibrates or “learns” battery capac-

of available battery charge. The

ity in the full course of a discharge

bq2040 directly supports capacity

cycle from full to empty.

➤ Provides accurate measurement

of available charge in NiCd,

NiMH, and Li-Ion batteries

➤ Supports SBS v1.0 data set and

two-wire interface

monitoring for NiCd, NiMH, and Li-

➤ Monitors charge FET in Li-Ion

Ion battery chemistries.

The bq2040 may operate directly

from three nickel chemistry cells.

With the REF output and an exter-

nal transistor, a simple, inexpensive

regulator can be built to provide

V_CCfor other battery cell configu-

rations.

pack protection circuit

The bq2040 uses the System Man-

agement Bus v1.0 (SMBus) protocol

and supports the Smart Battery

Data (SBData) commands. The

bq2040 also supports the SBData

charge control functions. Battery

state-of-charge, remaining capacity,

remaining time, and chemistry are

available over the serial link.

Battery-charge state can be directly

indicated using a four-segment LED

display to graphically depict battery

full-to-empty in 25% increments.

➤ Designed for battery pack inte-

gration

- ^{Low operating current}

- ^{Complete circuit can fit on less}

than ¾ square inch of PCB

space

An external EEPROM is used to

program initial values into the

bq2040 and is necessary for proper

operation.

➤ Supports SBS charge control

commands for NiCd, NiMH, and

Li-Ion

➤ Drives a four-segment LED dis-

play for remaining capacity

indication

➤ 16-pin narrow SOIC

Pin Connections

Pin Names

SB

Battery sense input

V_CC

3.0–6.5V

PSTAT Protector status input

SMBD SMBus data input/output

SMBC SMBus clock

V

1

2

3

4

5

6

16

15

14

13

12

11

V

ESCL

EEPROM clock

CC

OUT

ESDA EEPROM data

ESCL

ESDA

REF

LED_1-4LED segment 1-4

SMBC

SMBD

PSTAT

SB

REF

Voltage reference output

EEPROM supply output

V_SS

SR

System ground

LED

1

2

3

V_OUT

Sense resistor input

Display control input

DISP

7

8

10

9

DISP

SR

4

V

SS

16-Pin Narrow SOIC

PN204001.eps

SLUS005–JUNE 1999 E

1

bq2040

Display control input

DISP

Pin Descriptions

DISP high disables the LED display. DISP

floating allows the LED display to be active

during charge if the rate is greater than

100mA. DISP low activates the display for

4 seconds.

Supply voltage input

V_CC

Serial memory clock

ESCL

Output used to clock the data transfer be-

tween the bq2040 and the external non-

volatile configuration memory.

Secondary battery input

SB

Monitors the pack voltage through a high-

impedance resistor divider network. The

pack voltage is reported in the SBD register

function Voltage (0x09) and is monitored for

end-of-discharge voltage and charging volt-

age parameters.

ESDA

Serial memory data and address

Bidirectional pin used to transfer address

and data to and from the bq2040 and the ex-

ternal nonvolitile configuration memory.

LED display segment outputs

LED₁–

LED₄

Protector status input

PSTAT

Each output may drive an external LED.

Ground

Provides overvoltage status from the Li-Ion

protector circuit and can initiate a charge sus-

pend request.

V_SS

SR

Sense resistor input

SMBus data

SMBD

SMBC

REF

The voltage drop (V_SR) across pins SR and

V_SSis monitored and integrated over time

to interpret charge and discharge activity.

The SR input is connected to the sense re-

sistor and the negative terminal of the

battery. V_SR< V_SSindicates discharge, and

V_SR> V_SSindicates charge. The effective

voltage drop, V_SRO, as seen by the bq2040

is V_SR+ V_OS. (See Table 3.)

Open-drain bidirectional pin used to transfer

address and data to and from the bq2040.

SMBus clock

Open-drain bidirectional pin used to clock

the data transfer to and from the bq2040.

Reference output for regulator

REF provides a reference output for an op-

tional FET-based micro-regulator.

Supply output

V_OUT

Supplies power to the external EEPROM con-

figuration memory.

2

bq2040

Figure 1 shows a typical battery pack application of the

bq2040 using the LED capacity display, the serial port,

and an external EEPROM for battery pack program-

ming information. The bq2040 must be configured and

calibrated for the battery-specific information to ensure

proper operation. Table 1 outlines the configuration in-

formation that must be programmed in the EEPROM.

Functional Description

General Operation

The bq2040 determines battery capacity by monitoring

the amount of charge put into or removed from a re-

chargeable battery. The bq2040 measures discharge

and charge currents, estimates self-discharge, and

monitors the battery for low-battery voltage thresholds.

The charge is measured by monitoring the voltage

across a small-value series sense resistor between the

battery's negative terminal and ground. The available

battery charge is determined by monitoring this voltage

over time and correcting the measurement for the envi-

ronmental and operating conditions.

An internal temperature sensor eliminates the need

for an external thermistor—reducing cost and compo-

nents. An internal, temperature-compensated time-

base eliminates the need for an external resonator,

further reducing cost and components. The entire cir-

3

cuit in Figure 1 can occupy less than square inch of

4

board space.

(Optional)

V

CC

OUT

REF

ESCL

ESDA

LED1

LED2

LED3

LED4

SMBC

SMBD

PSTAT

SB

DISP

SR

V

SS

bq2040

Chart 1

For bq2040 With No D8

No. of Cells

R5

301K

499K

698K

R11

604K

806K

604K

R4

Q1

100K

2

BSS138

2N7002

3

4

(Optional)

6

8

9

499K

698K

806K

909K

499K

806K

100K

BSS138

499K

604K

909K

100K

86.5K

2N7002

10

12

2040LED.eps

Figure 1. Battery Pack Application Diagram—LED Display

3

bq2040

Table 1. Configuration Memory Map

Parameter Name

Address

Description

Length

8 bits

Units

NA

Number of EEPROM data locations

must = 0x64

EEPROM length

0x00

0x01

EEPROM check1

Remaining time alarm

Remaining capacity alarm

Reserved

EEPROM data integrity check byte, must = 0x5b

8 bits

NA

0x02/0x03 Sets RemainingTimeAlarm (0x02)

0x04/0x05 Sets RemainingCapacityAlarm (0x01)

0x06/0x07 Reserved for future use

16 bits minutes

16 bits

96 bits

16 bits

8 bits

mAh

NA

Initial charging current

Charging voltage

Battery status

0x08/0x09 Sets the initial charging current

0x0a/0x0b Sets ChargingVoltage (0x15)

0x0c/0x0d Initializes BatteryStatus (0x16)

0x0e/0x0f Initializes and stores CycleCount (0x17)

0x10/0x11 Sets DesignCapacity (0x18)

mA

mV

NA

Cycle count

cycles

mAh

mV

NA

Design capacity

Design voltage

0x12/0x13 Sets DesignVoltage (0x19)

Specification information

Manufacture date

Serial number

0x14/0x15 Programs SpecificationInfo (0x1a)

0x16/0x17 Programs ManufactureDate (0x1b)

0x18/0x19 Programs SerialNumber (0x1c)

0x1a/0x1b Sets ChargingCurrent (0x14)

NA

Fast-charging current

mA

mAh

NA

Maintenance-charge current 0x1c/0x1d Sets the trickle current request

Reserved

0x1e/0x1f Reserved must = 0x0000

Manufacturer name

Current overload

Battery low %

Reserved

0x20-0x2b Programs ManufacturerName (0x20)

0x2c/0x2d Sets the overload current threshold

mA

%

0x2e

0x2f

Sets the battery low amount

Reserved for future use

8 bits

NA

Device name

0x30-0x37 Programs DeviceName (0x21)

Sets the upper limit of the taper current for charge

64 bits

NA

Li-Ion taper current

0x38/0x39

16 bits

mA

termination

Maximum overcharge limit

Reserved

0x3a/0x3b Sets the maximum amount of overcharge

16 bits

8 bits

48 bits

16 bits

8 bits

NA

0x3c

0x3d

0x3e

0x3f

Reserved must = 0x00

Access protect

Locks commands outside of the SBS data set

Initializes FLAGS1

FLAGS1

FLAGS2

Initializes FLAGS2

Device chemistry

Current measurement gain

Battery voltage offset

Temperature offset

0x40-0x45 Programs DeviceChemistry (0x22)

0x46/0x47 Sense resistor calibration value

0x48

0x49

Voltage calibration value

Temperature calibration value

Maximum temperature and

∆T step

Sets the maximum charge temperature and the ∆T

step for ∆T/∆t termination

0x4a

8 bits

NA

4

bq2040

Table 1. Configuration Memory Map (Continued)

Parameter Name

Charge efficiency

Address

Description

Length

Units

0x4b

Sets the high/low charge rate efficiencies

8 bits

NA

Sets the percent at which the battery is consid-

ered fully charged

Full charge percentage

Digitial filter

0x4c

0x4d

0x4e

0x4f

8 bits

NA

Sets the minimum charge/discharge threshold

Programs the current integration gain to the

sense resistor value

Current integration gain

Self-discharge rate

Manufacturer data

Voltage gain1

Sets the battery’s self-discharge rate

8 bits

48 bits

16 bits

NA

0x50-0x55 Programs ManufacturerData (0x23)

0x56/0x57 Battery divider calibration value

0x58-0x59 Reserved

Reserved

Sets the charge current request when the battery

EDVF charging current

End of discharge voltage1

0x5a/0x5b

16 bits

NA

voltage is less than EDVF

0x5c/0x5d Sets EDV1

16 bits

8 bits

NA

End of discharge voltage final 0x5e/0x5f Sets EDVF

Full-charge capacity

∆t step

0x60/0x61 Initializes and stores FullChargeCapacity (0x10)

mAh

NA

0x62

0x63

Sets the ∆t step for ∆T/∆t termination

Sets ∆T/∆t hold-off timer

Hold-off time

8 bits

NA

EEPROM data integrity check byte

must = 0xb5

EEPROM check 2

Reserved

0x64

8 bits

NA

0x65-0x7f Reserved for future use

5

bq2040

Voltage Thresholds

Layout Considerations

In conjunction with monitoring V_SRfor charge/discharge

currents, the bq2040 monitors the battery potential

through the SB pin. The voltage potential is deter-

mined through a resistor-divider network per the fol-

lowing equation:

The bq2040 measures the voltage differential between

the SR and V_SSpins. V_OS(the offset voltage at the SR

pin) is greatly affected by PC board layout. For optimal

results, the PC board layout should follow the strict rule

of a single-point ground return. Sharing high-current

ground with small signal ground causes undesirable

noise on the small signal nodes. Additionally, in refer-

ence to Figure 1:

R₅

R₄

MBV

2.25

=

− 1

where MBV is the maximum battery voltage, R₅is con-

nected to the positive battery terminal, and R₄is con-

nected to the negative battery terminal. R₅/R₄should be

rounded to the next higher integer. The voltage at the

SB pin (V_SB) should never exceed 2.4V.

n

The capacitors (C1 and C2) should be placed as close as

possible to the SB and V_CCpins, and their paths to V_SS

should be as short as possible. A high-quality ceramic

capacitor of 0.1µf is recommended for V_CC

.

n

The sense resistor capacitor (C3) should be placed as

close as possible to the SR pin.

The battery voltage is monitored for the end-of-

discharge voltages (EDV1 and EDVF) and for alarm

warning conditions. EDV threshold levels are used to de-

termine when the battery has reached a programmable

“empty” state. The bq2040 generates an alarm warning

when the battery voltage exceeds the maximum charg-

ing voltage by 5% or if the voltage is below EDVF. The

battery voltage gain, the two EDV thresholds, and the

charging voltage are programmable in the EEPROM.

The bq2040 should be in thermal contact with the

cells for optimum temperature measurement.

Gas Gauge Operation

The operational overview diagram in Figure 2 illus-

trates the operation of the bq2040. The bq2040 accumu-

lates a measure of charge and discharge currents, as

well as an estimation of self-discharge. Charge currents

are compensated for temperature and state-of-charge of

the battery. Self-discharge is temperature-compensated.

If V_SBis below either of the two EDV thresholds, the associ-

ated flag is latched and remains latched, independent of

V_SB, until the next valid charge.

EDV monitoring may be disabled under certain condi-

tions. If the discharge current is greater than the value

stored in location 0x2c and 0x2d in the EEPROM (EE

0x2c/0x2d), EDV monitoring is disabled and resumes af-

ter the current falls below the programmed value.

The main counter, RemainingCapacity (RM), represents

the available battery capacity at any given time. Battery

charging increments the RM register, whereas battery dis-

charging and self-discharge decrement the RM register

and increment the internal Discharge Count Register

(DCR).

Reset

The bq2040 is reset when first connected to the battery

pack. On power-up, the bq2040 initializes and reads the

EEPROM configuration memory. The bq2040 can also

be reset with a command over the SMBus. The software

reset sequence is the following: (1) write MaxError

(0x0c) to 0x0000; (2) write the reset register (0x64) to

0x8009. A software reset can only be performed if the

bq2040 is in an unlocked state as defined by the value in

location 0x3d of the EEPROM (EE 0x3d) on power-up.

The Discharge Count Register is used to update the

FullChargeCapacity (FCC) register only if a complete

battery discharge from full to empty occurs without any

partial battery charges. Therefore, the bq2040 adapts

its capacity determination based on the actual condi-

tions of discharge.

The battery's initial full capacity is set to the value stored

in EE 0x60-0x61. Until FCC is updated, RM counts up to,

but not beyond, this threshold during subsequent charges.

Temperature

The battery’s empty state is also programmed in the

EEPROM. The battery low percentage (EE 0x2e) stores

the percentage of FCC that will be written to RM when

the battery voltage drops below the EDV1 threshold.

The bq2040 monitors temperature sensing using an in-

ternal sensor. The temperature is used to adapt charge

and self-discharge compensations as well as to monitor

for maximum temperature and ∆T/∆t during a bq2040

controlled charge. Temperature may also be accessed

over the SMBus with command 0x08.

1. FullChargeCapacity or learned-battery

capacity:

FCC is the last measured discharge capacity of the

battery. On initialization (application of V_CCor reset),

FCC is set to the value stored in the EEPROM. Dur-

6

bq2040

Charge

Current

Discharge

Current

Self-Discharge

Timer

Inputs

State-of-charge

and

Temperature

Compensation

Temperature

Compensation

+

-

Full

Charge

Capacity

(FCC)

Discharge

Count

Register

(DCR)

Remaining

Capacity

(RM)

+

<

Main Counters

and Capacity

Reference (FCC)

Qualified

Transfer

Temperature, Other Data

Chip-Controlled

Available Charge Serial Interface

LED Display

Two-Wire

Outputs

FG294501.eps

Figure 2. Operational Overview

ing subsequent discharges, FCC is updated with the

latest measured capacity in the Discharge Count Reg-

ister plus the battery low amount, representing a dis-

charge from full to below EDV1. A qualified dis-

charge is necessary for a capacity transfer from the

DCR to the FCC register. Once updated, the bq2040

writes the new FCC to the EEPROM. The FCC also

serves as the 100% reference threshold used by the

relative state-of-charge calculation and display.

4. Discharge Count Register (DCR):

The DCR counts up during discharge independent

of RM and can continue increasing after RM has

decremented to 0. Prior to RM = 0, both discharge

and self-discharge increment the DCR. After RM

= 0, only discharge increments the DCR. The DCR

resets to 0 when RM = FCC and stops counting at

EDV1 on discharge. The DCR does not roll over but

stops counting when it reaches FFFFh.

2. DesignCapacity (DC):

FCC is updated on the first charge after a qualified

discharge to EDV1. The updated FCC equals the

battery low percentage times the current FCC plus

the DCR value. A qualified discharge to EDV1 oc-

curs if all of the following conditions exist:

The DC is the user-specified battery capacity and is

programmed from external EEPROM. The DC also

provides the 100% reference for the absolute dis-

play mode.

3. RemainingCapacity (RM):

n

No valid charge initiations (charges greater than

10mAh, where V_SRO> +V_SRDoccurred during

the period between RM = FCC and EDV1 de-

tected.

RM counts up during charge to a maximum value of

FCC and down during discharge and self-discharge to

0. RM is set to the battery low amount after the

EDV1 threshold has been reached. If RM is already

equal to or less than the battery low amount, RM is

not modified. If RM reaches the battery low amount

before the battery voltage falls below EDV1 on dis-

charge, RM stops counting down until the EDV1

threshold is reached. RM is set to 0 when the battery

voltage reaches EDVF. To prevent overstatement of

charge during periods of overcharge, RM stops in-

crementing when RM = FCC. RM may optionally

be written to a user-defined value when fully

charged if the battery pack is under bq2040 charge

control. On initialization, RM is set to 0.

n

The self-discharge count is not more than

256mAh.

The low temperature fault bit in FLAGS2 is not

set when the EDV1 level is reached during dis-

charge.

n

Battery voltage is not more than 256mV below

the EDV1 threshold when EDV1 is set.

The valid discharge flag (VDQ) in FLAGS1 indi-

cates whether the present discharge is valid for an

FCC update. FCC cannot be reduced by more than

256mAh during any single cycle.

7

bq2040

Charge Counting

Current Taper

Charge activity is detected based on a positive voltage

on the SR input. If charge activity is detected, the

bq2040 increments RM at a rate proportional to V_SRO

and, if enabled, activates an LED display. Charge ac-

tions increment the RM after compensation for charge

state and temperature.

For Li-Ion charge control, the ChargingVoltage must be

set to the desired pack voltage during the constant volt-

age charge phase. The bq2040 detects a current taper

termination when it measures the pack voltage to be

within 128mV of the requested charging voltage and

when the AverageCurrent is less than the programmed

threshold in EE 0x38—0x39 and non-zero for at least

100s.

The bq2040 determines charge activity sustained at a

continuous rate equivalent to V_SRO> +V_SRD. A valid

charge equates to sustained charge activity

greater than 10 mAh. Once a valid charge is detected,

charge threshold counting continues until V_SROfalls be-

∆T/∆t

The ∆T/∆t used by the bq2040 is programmable in both

the temperature step (1.6°C–4.6°C) and time step (20

seconds–320seconds). Typical settings for 1°C/min in-

clude 2°C over 120 seconds and 3°C over 180 seconds.

Longer times are required for increased slope resolution.

low V_SRD

.

V_SRDis a programmable threshold as de-

scribed in the Digital Magnitude Filter section.

Discharge Counting

∆T

∆t

∆T

∆t

All discharge counts where V_SRO< -V_SRDcause the RM

register to decrement and the DCR to increment. V_SRD

is a programmable threshold as described in the Digital

Magnitude Filter section.

is set by the formula:

=

o

[(lower nibble of EE 0x4a) 2 + 16]/ 10

C

[320 − (EE 0x62) 20)]

s

Self-Discharge Estimation

In addition to the ∆T/∆t timer, there is a hold-off timer,

which starts when the battery is being charged at more

than 255mA and the temperature is above 25°C. Until

this timer expires, ∆T/∆t is suspended. If the tempera-

ture falls below 25°C, or if charging current falls below

255mA, the timer is reset and restarts only if these con-

ditions are once again within range. The hold-off time is

programmed in EE 0x63.

The bq2040 continuously decrements RM and incre-

ments DCR for self-discharge based on time and temper-

ature provided that the discharge flag in BatteryStatus

is set (charge not detected). The bq2040 self-discharge

estimation rate is programmed in EE 0x4f and can be

set from 0 to 25% per day for 20–30°C. This rate approx-

imately doubles for every 10°C increase until the tem-

perature is ≥ 70°C or halves every 10°C decrease until

the temperature is < 10°C.

Charge Termination

Charge Control

Once the bq2040 detects a valid charge termination, the

Fully_Charged, Terminate_Charge_Alarm, and the

Over_Charged_Alarm bits are set in BatteryStatus, and

the requested charge current is set to zero. Once the

terminating conditions cease, the Termi-

nate_Charge_Alarm and the Over_Charged_Alarm are

cleared, and the requested charging current is set to the

maintenance rate. The bq2040 requests the mainte-

nance rate until RM falls below the amount determined

by the programmable full- charge percentage. Once this

occurs, the Fully_Charged bit is cleared, and the re-

quested charge current and voltage are set to the

fast-charge rate.

The bq2040 supports SBS charge control by broadcast-

ing the ChargingCurrent and the ChargingVoltage to

the Smart Charger address. The bq2040 broadcasts

charging commands every 10 seconds; the broadcasts

can be disabled by writing bit 14 of BatteryMode to 1.

On reset, the initial charging current broadcast to the

charger is set to the value programmed in EE 0x08-

0x09. The bq2040 updates the value used in the charg-

ing current broadcasts based on the battery’s state of

charge, voltage, and temperature.

The bq2040 internal charge control is compatible with

nickel-based and Li-Ion chemistries. The bq2040 uses

current taper detection for Li-Ion primary charge termi-

nation and ∆T/∆t for nickel based primary charge termi-

nation. The bq2040 also provides a number of safety

terminations based on battery capacity, voltage, and

temperature.

Bit 4 (CC) in FLAGS2 determines whether RM is modi-

fied after a ∆T/∆t or current taper termination occurs. If

CC = 1, RM may be set from 0 to 100% of the FullChar-

geCapacity as defined in EE 0x4c. If RM is below the

full-charge percentage, RM is set to the full-charge per-

centage of FCC. If RM is above the full-charge percent-

age, RM is not modified.

8

bq2040

Charge Suspension

Count Compensations

The bq2040 may temporarily suspend charge if it detects

a charging fault. The charging faults include the follow-

ing conditions:

Charge activity is compensated for temperature and

state-of-charge before updating the RM and/or DCR.

Self-discharge estimation is compensated for tempera-

ture before updating RM or DCR.

Maximum Overcharge: If charging continues for

more than the programmed maximum overcharge

limit as defined in EE 0x3a—0x3b beyond RM=FCC,

the Fully_Charged bit is set, and the requested

charging current is set to the maintenance rate.

Charge Compensation

Charge efficiency is compensated for state-of-charge,

temperature, and battery chemistry. The charge effi-

ciency is adjusted using the following equations:

Overvoltage: An over-voltage fault exists when the

bq2040 measures a voltage more than 5% above the

1.) RM = RM * (Q _EFC− Q _ET

)

ChargingVoltage.

When the bq2040 detects an

where RelativeStateOfCharge < FullChargePercentage,

and Q _EFCis the programmed fast-charge efficiency vary-

ing from 0.75 to 1.0.

overvoltage condition, the requested charge current is

set to 0 and the Terminate_Charge_Alarm bit is set

in BatteryStatus. The alarm bit is cleared when the

current drops below 256mA and the voltage is less

than 105% of ChargingVoltage.

2.) RM = RM * (Q _ETC− Q _ET

)

where RelativeStateOfCharge ≥ FullChargePercentage

and Q _ETCis the programmed maintenance (trickle)

charge efficiency varying from 0.75 to 1.0.

Overcurrent: An overcurrent fault exists when the

bq2040 measures a charge current more than 25%

above the ChargingCurrent. If the ChargingCurrent

is less than 1024mA, an overcurrent fault exists if the Q _ETis used to adjust the charge efficiency as the battery

charge current is more than 1mA above the lowest

multiple of 256mA that exceeds the ChargingCurrent.

When the bq2040 detects an overcurrent condition, the

temperature increases according to the following:

Q _ET= 0 if 30°C

T

<

requested charge current is set to

0 and the

Q _ET= 0.02 if 30°C ≤ T < 40°C

Q _ET= 0.05 if T ≥ 40°C

Terminate_Charge_Alarm bit is set in Battery Status.

The alarm bit is cleared when the current drops below

256mA.

Q_ETis 0 over the entire temperature range for Li-Ion.

Maximum Temperature: When the battery

temperature equals the programmed maximum

temperature, the requested charge current is set to

Digital Magnitude Filter

The bq2040 has a programmable digital filter to elimi-

nate charge and discharge counting below a set

threshold, V_SRD. Table 2 shows typical digital filter

settings. The proper digital filter setting can be calcu-

lated using the following equation.

zero

and

the

Over_Temp_Alarm

and

the

Terminate_Charge_Alarm bits are set in Battery

Status. The Over_Temp_Alarm bit is cleared when

the temperature drops to 43°C below the maximum

temperature threshold minus 5°C.

45

PSTAT: When the PSTAT input is ≥1.5V, the

DMF =

requested charge current is set to

0

and the

VSRD

Terminate_Charge_Alarm bit is set in BatteryStatus

if the Discharging flag is not set. The alarm bit is

cleared when the PSTAT input is <1.0V or the

Discharging flag is set.

Table 2. Typical Digital Filter Settings

DMF

75

DMF Hex.

V_SRD(mV)

0.60

Low Temperature: When the battery temperature

is less than 12°C (LTF bit in FLAGS2 set), the

requested charge current is set to the maintenance

rate. Once the temperature is above 15°C, the

requested charge current is set to the fast rate.

4B

64

100

150

175

200

0.45

96

0.30

AF

C8

0.26

Undervoltage: When the battery voltage is below

the EDVF threshold, the requested charge current is

set to the EDVF rate stored in EE0x5a/0x5b. Once

the voltage is above EDVF, the requested charge

current is set to the fast or maintenance rate

depending on the state of the LTF bit.

0.23

9

bq2040

Table 3. bq2040 Current-Sensing Errors

Symbol

Parameter

Typical

Maximum

Units

Notes

V_OS

INL

Offset referred to V_SR

± 75

± 150

µV

DISP = V_CC.

Integrated non-linearity

error

Add 0.1% per °C above or below 25°C

and 1% per volt above or below 4.25V.

± 1

± 4

± 1

%

Integrated non-

repeatability error

Measurement repeatability given

similar operating conditions.

INR

± 0.5

and Remaining_Capacity_Alarm is set. V_SBbelow EDVF

(EDVF = 1) disables the display output.

Error Summary

Capacity Inaccurate

Microregulator

The FCC is susceptible to error on initialization or if no

updates occur. On initialization, the FCC value includes

the error between the design capacity and the actual ca-

pacity. This error is present until a qualified discharge

occurs and FCC is updated (see the DCR description).

The other cause of FCC error is battery wear-out. As the

battery ages, the measured capacity must be adjusted to

account for changes in actual battery capacity. Periodic

qualified discharges from full to empty will minimize er-

rors in FCC.

The bq2040 can operate directly from three nickel chem-

istry cells. To facilitate the power supply requirements

of the bq2040, an REF output is provided to regulate an

external low-threshold n-FET. A micropower source for

the bq2040 can be built inexpensively using a 2N7002 or

BSS138 FET and an external resistor. (See Figure 1.)

The value of R11 depends on the battery pack’s nominal

voltage.

Communicating With the bq2040

Current-Sensing Error

Table 3 illustrates the current-sensing error as a func-

The bq2040 includes a simple two-pin (SMBC and

SMBD) bi-directional serial data interface. A host proc-

essor uses the interface to access various bq2040 regis-

ters; see Table 4. This method allows battery character-

istics to be monitored easily. The open-drain SMBD and

SMBC pins on the bq2040 are pulled up by the host sys-

tem, or may be connected to V_SS, if the serial interface is

not used.

tion of V_SR

. A digital filter eliminates charge and dis-

charge counts to the RM register when -V_SRD< V_SRO

+ V_SRD

<

.

Display

The bq2040 can directly display capacity information us-

ing low-power LEDs. The bq2040 displays the battery

charge state in either absolute or relative mode. In rela-

tive mode, the battery charge is represented as a per-

centage of the FCC. Each LED segment represents 25%

of the FCC.

The interface uses a command-based protocol, where the

host processor sends the battery address and an eight-

bit command byte to the bq2040. The command directs

the bq2040 to either store the next data received to a

register specified by the command byte or output the

data specified by the command byte.

In absolute mode, each segment represents a fixed

amount of charge, 25% of the DesignCapacity. As the

battery wears out over time, it is possible for the FCC to

be below the design capacity. In this case, all of the

LEDs may not turn on in absolute mode, representing

the reduction in the actual battery capacity.

bq2040 Data Protocols

The host system, acting in the role of a Bus master, uses

the read word and write word protocols to communicate

integer data with the bq2040. (See Figure 3).

When DISP is tied to V_CC, the LED_1-4outputs are inac-

tive. When DISP is left floating, the display becomes ac-

tive whenever the bq2040 detects a charge rate of

100mA or more. When pulled low, the segment outputs

become active immediately for a period of approximately

4 seconds. The DISP pin must be returned to float or

V_CCto reactivate the display.

Host-to-bq2040 Message Protocol

The Bus Host communicates with the bq2040 using one

of three protocols:

n

Read word

Write word

LED₁blinks at a 4Hz rate indicating a low battery con-

dition whenever the display is active, EDVF is not set,

n

10

bq2040

1

7

1

0

1

8

1

8

1

8

1

Battery Address

0001011

S

A

Command Code

A

Data byte low

A

Data byte high

A

P

Write Word

1

7

1

0

1

8

1

7

1

Battery Address

0001011

S

A

Command Code

A

S

Battery Address

A

8

1

8

1

Data byte low

A

Data byte high

A

P

System Host

bq2040

Read Word

1

7

1

0

1

8

1

7

1

Battery Address

0001011

S

A

Command Code

A

S

Battery Address

A

A – ACKNOWLEDGE

A – NOT ACKNOWLEDGE

S – START

8

1

8

1

8

1

8

1

Byte Count =N

A

Data byte 1

A

Data byte 2

A

Data byte N

A

P

P – STOP

Block Read

FG204001.eps

Figure 3. Host Communication Protocols

n

Read block

Input/Output: unsigned integer. This sets/returns

the value where the Remaining_Time_Alarm bit is

set in Battery Status.

The particular protocol used is a function of the com-

mand. The protocols used are shown in Figure 3.

Units: minutes

Host-to-bq2040 Messages

(see Table 4)

Range: 0 to 65,535 minutes

BatteryMode() (0x03)

ManufacturerAccess() (0x00)

This read/write word selects the various battery opera-

tional modes. The bq2040 supports the battery capacity

information specified in mAh. This function also deter-

mines whether the bq2040 charging values are broad-

casted to the Smart Battery Charger address.

This read/write word is an open location.

Input/Output: word.

RemainingCapacityAlarm() (0x01)

This function sets or returns the low-capacity alarm

value. When RM falls below the RemainingCapac-

ityAlarm value initialized from the external EE-

PROM, the Remaining_Capacity_Alarm bit is set in

BatteryStatus. The system may alter this alarm dur-

ing operation.

Writing bit 14 to 1 disables voltage and current Master

Mode broadcasts to the Smart Battery Charger. Bit 14 is

automatically reset to 0 if SMBC and SMBD = 0 for

greater than 2 seconds (i.e. pack removal).

Writing bit 13 to 1 disables all Master Mode broadcasts

including alarm messages to the Smart Battery Charger

and Host. The bit remains set until overwritten. Pro-

gramming bit 3 of FLAGS2 in the EEPROM (EE0x3f)

initializes this bit to a 1.

Input/Output: unsigned integer. This sets/returns

the value where the Remaining_Capacity_Alarm

bit is set in Battery Status.

Units: mAh

Bit 7 is the condition request flag. It is set when the

bq2040 is initialized from the EEPROM and reset when a

learning cycle has been completed. It is also set to a 1 if

CycleCount increases by 32 without a new learning cycle.

Range: 0 to 65,535mAh

RemainingTimeAlarm() (0x02)

AtRate() (0x04)

This function sets or returns the low remaining time

alarm value. When the AverageTimeToEmpty falls be-

low this value, the Remaining_Time_Alarm bit in Bat-

teryStatus is set. The default value for this register is

programmed in EE 0x02-0x03.. The system may alter

this alarm during operation.

This read/write word is the first half of a two-function

set used to set the AtRate value used in calculations

made by the AtRateTimeToFull and AtRateTime-

ToEmpty.

11

bq2040

Table 4. bq2040 Register Functions

Function

Code

0x00

0x01

0x02

0x03

0x04

0x05

0x06

0x07

0x08

0x09

0x0a

0x0b

0x0c

Access

read/write

read

Units

-

Defaults¹

ManufacturerAccess

RemaningCapacityAlarm

RemainingTimeAlarm

BatteryMode

-

E²

-

mAh

minutes

bit flag

mA

AtRate

-

AtRateTimeToFull

AtRateTimeToEmpty

AtRateOK

minutes

Boolean

0.1°K

mV

-

read

-

read

-

Temperature

read

2930

E²

0

Voltage

read

Current

read

mA

AverageCurrent

MaxError

read

mA

0

read

percent

mAh

100

-

RelativeStateOfCharge

AbsoluteStateOfCharge

RemainingCapacity

FullChargeCapacity

RunTimeToEmpty

AverageTimeToEmpty

AverageTimeToFull

ChargingCurrent

ChargingVoltage

Battery Status

0x0d

0x0e

0x0f

read

-

read

E²

-

0x10

0x11

0x12

0x13

0x14

0x15

0x16

0x17

0x18

0x19

0x1a

0x1b

0x1c

read

mAh

read

minutes

mA

read

-

read

-

read

E²

-

read

mV

read

bit flags

cycle

CycleCount

read

DesignCapacity

DesignVoltage

read

mAh

read

mV

SpecificationInfo

ManufactureDate

SerialNumber

read

-

read

-

read

integer

-

Reserved

0x1d - 0x1f

0x20

0x21

-

ManufacturerName

DeviceName

read

string

E²

read

Note:

1. Defaults after reset or power-up.

12

bq2040

Table 4. bq2040 Register Functions (Continued)

Function

DeviceChemistry

Code

0x22

0x23

0x2f

Access

read

Units

string

bit flags

-

Defaults¹

E²

ManufacturerData

read

FLAG1 and FLAG2

read

End of Discharge Voltage 1 (EDV1)

0x3e

read

End of Discharge Voltage Final

(EDVF)

0x3f

read

-

E²

Note:

1. Defaults after reset or power-up.

13

bq2040

n

When the AtRate value is positive, the

AtRateTimeToFull function returns the predicted

time to full-charge at the AtRate value of charge.

Temperature() (0x08)

This read-only word returns the cell-pack's internal

temperature.

n

When the AtRate value is negative, the

AtRateTimeToEmpty function returns the predicted

operating time at the AtRate value of discharge.

Output: unsigned integer. Returns the cell tem-

perature in tenths of degrees Kelvin increments.

Units: 0.1°K

Input/Output: signed integer. AtRate is positive

for charge and negative for discharge.

Range: 0 to +500.0°K

Units: mA

Granularity: 0.5°K or better

Accuracy: ±3°K after calibration

Range: -32,768mA to 32,767mA

AtRateTimeToFull() (0x05)

Voltage() (0x09)

This read-only word returns the predicted remaining

time to fully charge the battery at the AtRate value

(mA) and is valid only if read immediately after an

AtRate command.

This read-only word returns the cell-pack voltage (mV).

Output: unsigned integer. Returns the battery ter-

minal voltage in mV.

Output: unsigned integer. Returns the predicted

time to full charge.

Units: mV

Range: 0 to 65,535mV

Units: minutes

Granularity: 0.2% of DesignVoltage

Accuracy: ±1% of DesignVoltage after calibration

Range: 0 to 65,534min

Granularity: 2 min or better

Current() (0x0a)

Invalid Data Indication: 65,535 indicates that the

AtRate value is negative.

This read-only word returns the current through the

battery's terminals (mA).

AtRateTimeToEmpty() (0x06)

Output: signed integer. Returns the charge/dis-

charge rate in mA, where positive is for charge

and negative is for discharge

This read-only word returns the predicted remaining op-

erating time if the battery is discharged at the AtRate

value and is valid only if read immediately after an

AtRate command.

Units: mA

Range: 0 to 32,767mA for charge or 0 to

–32,768mA for discharge

Output: unsigned integer. Returns the predicted

time to empty.

Granularity: 0.2% of the DesignCapacity or better

Units: minutes

Accuracy: ±1% of the DesignCapacity after calibration

Range: 0 to 65,534min

Granularity: 2min or better

AverageCurrent() (0x0b)

Invalid Data Indication: 65,535 indicates that the

AtRate value is not negative.

This read-only word returns a rolling average of the cur-

rent through the battery's terminals. The AverageCur-

rent function returns meaningful values after the bat-

tery's first minute of operation.

AtRateOK() (0x07)

This read-only word returns a Boolean value that indi-

cates whether or not the EDVF flag has been set.

Output: signed integer. Returns the charge/dis-

charge rate in mA, where positive is for charge

and negative is for discharge

Boolean: Indicates if the battery can supply addi-

tional energy.

Units: mA

Units: Boolean

Range: 0 to 32,767mA for charge or 0 to

–32,768mA for discharge

Range: TRUE ≠ 0, FALSE = 0

Granularity: 0.2% of the DesignCapacity or better

14

bq2040

Accuracy: ±1% of the DesignCapacity after cali-

bration

RemainingCapacity() (0x0f)

This read-only word returns the predicted remaining

battery capacity. The RemainingCapacity value is ex-

pressed in mAh.

MaxError() (0x0c)

Returns the expected margin of error (%) in the state of

charge calculation.

Output: unsigned integer. Returns the estimated re-

maining capacity in mAh.

Output: unsigned integer. Returns the percent un-

certainty for selected information.

Units: mAh

Range: 0 to 65,535mAh

Units: %

Granularity: 0.2% of DesignCapacity or better

Range: 0 to 100%

Accuracy: ±MaxError FCC after circuit and ca-

pacity calibration

RelativeStateOfCharge() (0x0d)

This read-only word returns the predicted remaining

battery capacity expressed as a percentage of FullChar-

geCapacity (%). RelativeStateOfCharge is only

valid for battery capacities more than 1504mAh

and less than 10,400mAh.

FullChargeCapacity() (0x10)

This read-only word returns the predicted pack capacity

when it is fully charged. FullChargeCapacity defaults

to the value programmed in the external EEPROM until

a new pack capacity is learned. The new FCC is stored

to EEPROM within 400ms of a valid charge after a

qualified discharge.

Output: unsigned integer. Returns the percent of re-

maining capacity.

Units: %

Output: unsigned integer. Returns the estimated full

charge capacity in mAh.

Range: 0 to 100%

Granularity: 1%

Units: mAh

Accuracy: ±MaxError after circuit and capacity

calibration

Range: 0 to 65,535mAh

Granularity: 0.2% of DesignCapacity or better

AbsoluteStateOfCharge() (0x0e)

Accuracy: ±MaxError FCC after circuit and ca-

pacity calibration

This read-only word returns the predicted remaining

battery capacity expressed as a percentage of DesignCa-

pacity (%). Note that AbsoluteStateOfCharge can return

values greater than 100%. Absolute StateOfCharge

is only valid for battery capacities more than

1504mAh and less than 10,400mAh.

RunTimeToEmpty() (0x11)

This read-only word returns the predicted remaining

battery life at the present rate of discharge (minutes).

The RunTimeToEmpty value is calculated based on

Current.

Output: unsigned integer. Returns the percent of

remaining capacity.

Output: unsigned integer. Returns the minutes of

operation left.

Units: %

Units: minutes

Range: 0 to 65,535%

Granularity: 1%

Range: 0 to 65,534min

Granularity: 2min or better

Accuracy: ±MaxError after circuit and capacity

calibration

Invalid data indication: 65,535 indicates battery is

not being discharged.

AverageTimeToEmpty() (0x12)

This read-only word returns the predicted remaining

battery life at the present average discharge rate (min-

utes). The AverageTimeToEmpty is calculated based on

AverageCurrent.

15

bq2040

Output: unsigned integer. Returns the minutes of

operation left.

BatteryStatus() (0x16)

This read-only word returns the battery status word.

Units: minutes

Output: unsigned integer. Returns the status reg-

ister with alarm conditions bitmapped as shown in

Table 5.

Range: 0 to 65,534min

Granularity: 2min or better

Some of the BatteryStatus flags (Remaining_Capac-

ity_Alarm and Remaining_Time_Alarm) are calculated

based on current. See Table 8 and 9 for definitions.

Invalid data indication: 65,535 indicates battery

is not being discharged.

AverageTimeToFull() (0x13)

Table 5. Status Register

This read-only word returns the predicted time until the

Smart Battery reaches full charge at the present aver-

age charge rate (minutes).

Alarm Bits

0x8000

0x4000

0x2000

0x1000

0x0800

0x0400

0x0200

0x0100

Over_Charged_Alarm

Terminate_Charge_Alarm

Reserved

Output: unsigned integer. Returns the remaining

time in minutes to full.

Units: minutes

Over_Temp_Alarm

Terminate_Discharge_Alarm

Reserved

Range: 0 to 65,534min

Granularity: 2min or better

Invalid data indication: 65,535 indicates battery

is not being charged.

Remaining_Capacity_Alarm

Remaining_Time_Alarm

Status Bits

ChargingCurrent() (0x14)

If enabled, the bq2040 sends the desired charging rate in

mA to the Smart Battery Charger.

0x0080

0x0040

0x0020

0x0010

Initialized

Discharging

Output: unsigned integer. Transmits/returns the

maximum charger output current in mA.

Fully_Charged

Fully_Discharged

Error Code

Units: mA

Range: 0 to 65,534mA

0x0000-

0x000f

Reserved for error codes

Granularity: 0.2% of the design capacity or better

Invalid data indication: 65,535 indicates that the

Smart Charger should operate as a voltage source

outside its maximum regulated current range.

CycleCount() (0x17)

This read-only word returns the number of charge/dis-

charge cycles the battery has experienced. A charge/dis-

charge cycle starts from a base value equivalent to the

battery's state-of-charge on completion of a charge cycle.

The bq2040 increments the cycle counter during the cur-

rent charge cycle if the battery has been discharged 15%

below the state-of-charge at the end of the last charge cy-

cle. This prevents false reporting of small charge/discharge

cycles. The cycle count is stored in EEPROM within

400ms of an update.

ChargingVoltage() (0x15)

If enabled, the bq2040 sends the desired voltage in mV

to the Smart Battery Charger.

Output: unsigned integer. Transmits/returns the

charger voltage output in mV.

Units: mV

Range: 0 to 65,534mV

Output: unsigned integer. Returns the count of

charge/discharge cycles the battery has

experienced.

Granularity: 0.2% of the DesignVoltage or better

Invalid data indication: 65,535 indicates that the

Smart Battery Charger should operate as a cur-

rent source outside its maximum regulated voltage

range.

Units: cycles

16

bq2040

Table 6. Bit Descriptions for FLAGS1 and FLAGS2

(MSB) 7

6

5

4

CC

-

3

-

2

1

0 (LSB)

OC

FLAGS2 DMODE

PSTAT

I_MIN

CHM

VQ

OV

LTF

EDV1

FLAGS1

VDQ

OVLD

EDVF

∆T/∆t

Note:

- = Reserved

Range: 0 to 65,535 cycles; 65,535 indicates battery

has experienced 65,535 or more cycles.

SerialNumber() (0x1c)

This read-only word returns a serial number. This

number, when combined with the ManufacturerName,

the DeviceName, and the ManufactureDate, uniquely

identifies the battery.

Granularity: 1 cycle

DesignCapacity() (0x18)

This read-only word returns the theoretical capacity of a

new pack. The DesignCapacity value is expressed in

mAh at the nominal discharge rate.

Output: unsigned integer

ManufacturerName() (0x20)

Output: unsigned integer. Returns the battery ca-

pacity in mAh.

This read-only string returns a character string where the

first byte is the number of characters available. The maxi-

mum number of characters is 11. The character string con-

tains the battery manufacturer's name. For example,

“Benchmarq” identifies the battery pack manufacturer as

Benchmarq.

Units: mAh

Range: 0 to 65,535mAh

DesignVoltage() (0x19)

Output: string or ASCII character string

This read-only word returns the theoretical voltage of

a new pack in mV.

DeviceName() (0x21)

This read-only string returns a character string where the

first byte is the number of characters available. The maxi-

mum number of characters is 7. The 7-byte character string

contains the battery's name. For example, a DeviceName of

“bq2040” indicates that the battery is a model bq2040.

Output: unsigned integer. Returns the battery's

normal terminal voltage in mV.

Units: mV

Range: 0 to 65,535mV

Output: string or ASCII character string

SpecificationInfo() (0x1a)

DeviceChemistry() (0x22)

This read-only word returns the specification re-

vision the bq2040 supports.

This read-only string returns a character string where

the first byte is the number of characters available. The

maximum number of characters is 5. The 5-byte charac-

ter string contains the battery's chemistry. For example,

if the DeviceChemistry function returns “NiMH,” the

battery pack contains nickel-metal hydride cells.

ManufactureDate() (0x1b)

This read-only word returns the date the cell was manu-

factured in a packed integer word. The date is packed

as follows: (year - 1980) 512 + month 32 + day.

Output: string or ASCII character string

Bits

ManufacturerData() (0x23)

Field Used

Day 0–4

Month 5–8

Year 9–15

Format

Allowable Value

5-bit binary 1–31 (corresponds to

This read-only string allows access to an up to 5-byte

manufacturer data string.

value date)

4-bit binary 1–12 (corresponds to

value month number)

Output: block data—data whose meaning is as-

signed by the Smart Battery's manufacturer.

7-bit binary 0–127 (corresponds to

value year biased by 1980)

17

bq2040

The CHM value is:

End of Discharge Voltage1 (0x3e)

This read-only word returns the first end-of-discharge

voltage programmed for the pack.

FLAGS2 Bits

7

6

5

4

3

2

1

0

Output: two’s complemented unsigned integer.

Returns battery end-of-discharge voltage pro-

grammed in EEPROM in mV.

-

CHM

-

Where CHM is:

End of Discharge VoltageF (0x3f)

0

1

Selects Nickel

Selects Li-Ion

This read-only word returns the final end-of-discharge

voltage programmed for the pack.

Bit 4, the Charge Control flag (CC), determines whether

a bq2040-based charge termination will set RM to a

user-defined programmable full charge capacity.

Output: two’s complemented unsigned integer.

Returns battery final end-of-discharge voltage pro-

grammed in EEPROM in mV.

The CC value is:

FLAGS1&2() (0x2f)

FLAGS2 Bits

This read-only register returns an unsigned integer rep-

resenting the internal status registers of the bq2040.

The MSB represents FLAGS2, and the LSB represents

FLAGS1. See Table 6 for the bit description for FLAGS1

and FLAGS2.

7

6

5

4

3

2

1

0

-

CC

-

Where CC is:

0

RM is not modified on valid bq2040

charge termination

FLAGS2

The Displa y Mode flag (DMODE), bit 7 determines

whether the bq2040 displays Relative or Absolute capac-

ity.

1

RM is set to a programmable percentage of

the FCC when a valid bq2040 charge termi-

nation occurs

The DMODE value is:

Bit 3 is reserved.

FLAGS2 Bits

Bit 2, the Overvoltage flag (OV), is set when the bq2040

detects a pack voltage 5% greater than the programmed

charging voltage. This bit is cleared when the pack volt-

age falls 5% below the programmed charging voltage.

7

6

5

4

3

2

1

0

DMODE

-

Where DMODE is:

The OV value is:

0

1

Selects Absolute display

Selects Relative display

FLAGS2 Bits

7

6

5

4

3

2

1

0

-

OV

-

Bit 6 reflects the high/low state of PSTAT. PSTAT ≥1.5V

generates a charge suspend condition.

The PSTAT value is:

Where OV is:

FLAGS2 Bits

0

1

Voltage < 1.05 ChargingVoltage

7

6

5

4

3

2

1

0

Voltage ≥ 1.05 ChargingVoltage

-

PSTAT

-

Bit 1, the Low Temperature Fault flag (LTF), is set when

Temperature is < 12°C and cleared when Temperature

is ≥ 15°C.

Where PSTAT is:

0

1

PSTAT input < 1.0V

The LTF value is:

PSTAT input ≥ 1.5V

FLAGS2 Bits

The Chemistry flag (CHM), bit 5, selects Li-Ion or nickel

compensation factors.

7

6

5

4

3

2

1

0

-

LTF

-

18

bq2040

Where LTF is:

The I_MINvalue is:

Where I_MINis:

0

1

Temperature > 15°C

Temperature < 12°C

0

A valid current taper termination condition

is not present.

Bit 0, the Overcurrent flag (OC), is set when Current is

25% greater than the programmed charging current. If

the charging current is programmed less than 1024mA,

overcurrent is set if Current is 256mA greater than the

programmed charging current. This flag is cleared when

Current falls below 256mA.

1

Valid current taper termination condition

detected.

The Valid Charge flag (VQ), bit 5, is set when V_SRO

≥

|V_SRD| and 10mAh of charge has accumulated. This bit

is cleared during a discharge and when V_SRO≤ |V_SRD|.

The OC value is:

FLAGS1 Bits

FLAGS2 Bits

7

6

5

4

3

2

1

0

7

6

5

4

3

2

1

0

-

VQ

-

OC

Where OC is:

The VQ value is:

Where VQ is:

0

Current is less than 1.25 ChargingCur-

rent or less than 256mA if charging current

is programmed less than 1024mA

0

1

V_{SRO ≤}|V_SRD|

V_SRO≥ |V_SRD| and 10mAh of charge has

accumulated

1

Current exceeds 1.25 ChargingCurrent or

256mA if the charging current is pro-

grammed less than 1024mA. This bit is

cleared if Current < 256mA.

Bit 4 is reserved.

The Valid Discharge flag (VDQ), bit 3, is set when a

valid discharge is occurring (discharge cycle valid for

learning new full charge capacity) and cleared if a par-

tial charge is detected, EDV1 is asserted when T < 0°C,

or self-discharge accounts for more than 256mAh of the

discharge.

FLAGS1

Bits 7 indicates that a ∆T/∆t termination condition

exists.

The ∆T/∆t value is:

FLAGS1 Bits

7

6

5

4

3

2

1

0

7

6

5

4

3

2

1

0

-

VDQ

-

∆T/∆t

The VDQ value is:

Where VDQ is:

Where ∆T/∆t is:

0

The ∆T/∆t rate drops below the pro-

grammed rate.

0

Self-discharge is greater than 256mAh,

EDV1 = 1 when T < 0°C or VQ = 1

1

On first discharge after RM=FCC

1

The ∆T/∆t rate exceeds the programmed

rate.

The Overload flag (OVLD), bit 2, is set when the dis-

charge current is greater than the programmed rate and

cleared when the discharge current falls below the pro-

grammed rate.

Bit 6 indicates that a current taper termination condi-

tion exists.

FLAGS1 Bits

7

6

5

4

3

2

1

0

7

6

5

4

3

2

1

0

-

I_MIN

-

OVLD

-

19

bq2040

The OVLD value is:

Where OVLD is:

SBD Seal

The bq2040 address space can be “locked” to enforce the

SBS specified access to each command code. To lock the

address space, the bq2040 must be initialized with EE

0x3d set to b0h. Once this is done, only commands

0x00-0x04 may be written. Attempting to write to any

other address will cause a “no acknowledge” of the data.

Reading will only be permitted from the command codes

listed in the SBD specification plus the five locations

designated as optional manufacturing functions 1–5

(0x2f, 0x3c–0x3f).

0

1

Current < programmed rate

Current > programmed rate

The First End-of-Discharge Voltage flag (EDV1), bit 1, is

set when Voltage < EDV1 and OVLD = 0 and cleared

when VQ = 1 and Voltage > EDV1.

FLAGS1 Bits

7

6

5

4

3

2

1

0

-

EDV1

-

Programming the bq2040

The EDV1 value is:

Where EDV1 is:

The bq2040 requires the proper programming of an ex-

ternal EEPROM for proper device operation. Each mod-

ule can be calibrated for the greatest accuracy, or gen-

eral “default” values can be used. An EV2200-40 pro-

gramming kit (interface board, software, and cable) for

an IBM-compatible PC is available from Benchmarq.

0

1

VQ = 1 and Voltage > EDV1

Voltage < EDV1 and OVLD = 0

The Final End-of-Discharge Voltage flag (EDVF), bit 0, is

set when Voltage < EDVF and OVLD = 0 and cleared

when VQ = 1 and Voltage > EDVF.

The bq2040 uses a 24LC01 or equivalent serial EE-

PROM (capable of read operation to 2.0V) for storing the

various initial values, calibration data, and string infor-

mation. Table 1 outlines the parameters and addresses

for this information. Tables 10 and 11 detail the various

register contents and show an example program value

for an 2400mAh 4-series Li-Ion battery pack, using a

50mΩ sense resistor.

FLAGS1 Bits

7

6

5

4

3

2

1

0

-

EDVF

The EDVF value is:

Where EDVF is:

0

1

VQ = 1 and Voltage > EDVF

Voltage < EDVF and OVLD = 0

Error Codes and Status Bits

Error codes and status bits are listed in Table 8 and Ta-

ble 9, respectively.

20

bq2040

Table 8. Error Codes (BatteryStatus() (0x16))

Error

Code

Access

Description

OK

0x0000 read/write bq2040 processed the function code without detecting any errors.

0x0001 read/write bq2040 is unable to process the function code at this time.

Busy

bq2040 cannot read or write the data at this time—try again

ReservedCommand

UnsupportedCommand

AccessDenied

0x0002 read/write

later.

0x0003 read/write bq2040 does not support the requested function code.

bq2040 detected an attempt to write to a read-only function

0x0004

write

code.

Overflow/Underflow

BadSize

0x0005 read/write bq2040 detected a data overflow or underflow.

bq2040 detected an attempt to write to a function code with an

incorrect size data block.

0x0006

write

UnknownError

0x0007 read/write bq2040 detected an unidentifiable error.

Note:

Reading the bq2040 after an error clears the error code.

21

bq2040

Table 9. BatteryStatus Bits

Alarm Bits

Set When:

Bit Name

Reset When:

The bq2040 detects a ∆T/∆t or cur-

rent taper termination. (Note:

∆T/∆t and current taper are valid

charge terminations.)

A discharge occurs or when the

∆T/∆t or current taper termination

condition ceases during charge.

OVER_CHARGED_ALARM

The bq2040 detects an over-current,

over-voltage, over-temperature,

∆T/∆t, or current taper condition

during charge.

A discharge occurs or when all condi-

tions causing the event cease.

TERMINATE_CHARGE_ALARM

OVER_TEMP_ALARM

Internal temperature falls to 43°C or

the maximum temperature threshold

minus 5°C.

The bq2040 detects that its internal

temperature is greater than the pro-

grammed value.

The bq2040 determines that it has

supplied all the charge that it can

without being damaged (Voltage <

EDVF).

Voltage > EDVF signifies that the

battery has reached a state of charge

sufficient for it to once again safely

supply power.

TERMINATE_DISCHARGE_ALARM

Either the value set by the Remain-

ingCapacityAlarm function is lower

than the Remaining Capacity or the

RemainingCapacity is increased by

charging.

The bq2040 detects that the Remain-

ingCapacity is less than that set by

the RemainingCapacityAlarm func-

tion.

REMAINING_CAPACITY_ALARM

REMAINING_TIME_ALARM

The bq2040 detects that the esti-

mated remaining time at the present

discharge rate is less than that set

by the RemainingTimeAlarm func-

tion.

Either the value set by the Remain-

ingTimeAlarm function is lower than

the AverageTimeToEmpty or a valid

charge is detected.

Status Bits

Set When:

Bit Name

Reset When:

The bq2040 loads from the EEPROM

(bit 7 set in EE0x0c).

INITIALIZED

A bad EEPROM load is detected.

The bq2040 determines that it is not Battery detects that it is being

DISCHARGING

being charged.

charged.

The bq2040 determines a valid

charge termination or a maximum

overcharge state.

RM discharges below the full charge

percentage.

FULLY_CHARGED

bq2040 determines that it has

supplied all the charge that it can

without being damaged.

RelativeStateOfCharge is greater

than or equal to 20%

FULLY_DISCHARGED

22

bq2040

Table 10. Example Register Contents

EEPROM

Address

EEPROM

Hex Contents

Example

Values

Low High Low High

Byte Byte Byte Byte

Description

Notes

EEPROM

length

0x00

64

5b

0a

100

91

Must be equal to 0x64.

Must be equal to 0x5b.

EEPROM check 1 0x01

Remaining time

alarm

0x02 0x03

00

10 minutes Sets the low time alarm level.

240mAh Sets the low capacity alarm level.

Remaining

capacity alarm

0x04 0x05

0x06 0x07

0x08 0x09

f0

00

60

00

09

Reserved

0

Not currently used by the bq2040.

Sets the initial charge request.

Initial charging

current

2400mA

Used to set the fast-charge voltage for the Smart

Charger.

Charging voltage

Battery status

Cycle count

0x0a 0x0b

0x0c 0x0d

0x0e 0x0f

d8

80

00

40

00

16600mV

128

0

Initializes BatteryStatus.

Contains the charge cycle count and can be set to zero

for a new battery.

Design capacity 0x10 0x11

60

40

09

38

2400mAh Normal battery pack capacity.

14400mV Nominal battery pack voltage.

Design voltage

0x12 0x13

Specification

information

0x14 0x15

10

00

1.0

Default value for this register in a 1.0 part.

Manufacture

date

May 1, 1996

= 8353

0x16 0x17

0x18 0x19

0x1a 0x1b

a1

12

60

20

27

09

Packed per the ManufactureDate description.

Contains the optional pack serial number.

Serial number

10002

Fast-charging

current

Used to set the fast-charge current for the Smart

Charger.

2400mA

Maintenance

Contains the desired maintenance current after fast-

charge termination by the bq2040.

0x1c 0x1d

0x1e 0x1f

0x2c 0x2d

00

70

00

17

0mA

0

charge current

Reserved

Must be programmed to 0x00.

Current

overload

Sets the discharge current at which EDV threshold

monitoring is disabled.

6000mA

Sets the battery capacity that RemainingCapacity is

reduced to at EDV1. The value equals 2.56 (%RM at

EDV1)

Battery low %

0x2e

08

3%

23

bq2040

Table 10. Example Register Contents (Continued)

EEPROM

Address

Hex

Contents

Low High Low High

Byte Byte Byte Byte

Example

Values

Description

Notes

Reserved

0x2f

00

10

0

Not currently used by the bq2040.

Li-Ion taper

current

Sets the upper taper limit for Li-Ion charge termina-

tion. Stored in 2’s complement.

0x38 0x39

ff

240mA

Maximum

overcharge

limit

Sets the maximum amount of overcharge before a

maximum overcharge charge suspend occurs.

Stored in 2’s complement.

0x3a 0x3b

0x3c

9c

100mAh

0

Reserved

00

Must be programmed to 0.

If the bq2040 is reset and bit 3 of this location is 0, the

bq2040 locks access to any command outside of the SBS

data set. Program to 0xb8 for full R/W access, 0xb0 for

SBD access only.

Access protect 0x3d

b0

00

b0

SBD access only

0

FLAGS1

FLAGS2

0x3e

0x3f

Initializes FLAGS1

Relative display

Li-Ion chemistry

bq2040 charge

control

Initializes FLAGS2.

The current gain measurement and current integra-

tion gain are related and defined for the bq2040 cur-

rent measurement. This word equals 192/sense re-

sistor value in ohms.

Current

measurement

0x46 0x47

0x48

00

fe

0f

3840

-2mV

13.8°C

gain¹

Used to adjust the battery voltage offset according to

the following:

Battery voltage

offset¹

Voltage = (V_SB(mV) + V_OFF

)

Voltage gain

The default value (zero adjustment) for the offset is

Temperature

offset¹

12.8°C or 0x80.

TOFF_NEW= TOFF_CURRENT

0x49

8a

+

(TEMP_ACTUAL- TEMP_REPORTED) 10

Maximum

temperature =

61.0°C

Maximum

temperature

and ∆T step

Maximum charge temperature is 69- (mt 1.6)°C (mt

= upper nibble). The ∆T step is (dT 2 + 16)/10°C

(dT = lower nibble).

0x4a

0x4b

5f

ff

∆T step = 4.6°C

Sets the fast-charge (high) and maintenance charge

(low) efficiencies. The upper nibbles sets the low effi-

ciency and the lower nibble adjusts the high effi-

ciency according to the equation:

Maintenance

compensation =

100%

Fast compensa-

tion = 100%

Charge

efficiency

Nibble = (efficiency% 256 - 196)/4

This packed field is the two’s complement of the de-

sired value in RM when the bq2040 determines a

full-charge termination. If RM is below this value,

RM is set to this value. If RM is above this value,

then RM is not adjusted.

Full-charge

percentage

0x4c

9c

100%

Note:

1. Can be adjusted to calibrate the battery pack.

24

bq2040

Table 10. Example Register Contents (Continued)

EEPROM

Address

Hex

Contents

Example

Values

Low High Low High

Byte Byte Byte Byte

Description

Notes

Used to set the digital magnitude filter as described in

Table 2.

Digital filter

0x4d

96

0.30mV

3.2/0.05

Represents the following: 3.2/sense resistor in ohms.

It is used by the bq2040 to scale the measured voltage

values on the SR pin in mA and mAh. This register

also compensates for variations in the reported sense

resistor value.

Current integra-

tion gain¹

0x4e

40

0

This packed field is the two’s complement of (52.73/x)

where x is the desired self-discharge rate per day (%)

at room temperature.

Self-discharge rate 0x4f

2d

0.25%

7.09

Voltage gain is packed as two units. For example, (R4

+ R5)/R4 = 7.09 would be stored as: whole number

stored in 0x57 as 7 and the decimal component stored

in 0x56 as 256 x 0.09 = 23(= 17h).

Voltage gain¹

Reserved

0x56 0x57 17

07

0x58 0x59 00

0x5a 0x5b 64

00

0

Should be programmed to 0.

EDVF charging

current

100mA

Contains the desired charge current below EDVF.

End of discharge

voltage 1

The value programmed is the two’s complement of the

threshold voltage in mV.

0x5c 0x5d 20

d1

d4

07

12000mV

11200mV

2000mA

20s

End-of-discharge

voltage final

The value programmed is the two’s complement of the

threshold voltage in mV.

0x5e 0x5f

40

Full charge

capacity

0x60 0x61 d0

This value sets the initial estimated pack capacity.

The ∆t step for ∆T/∆t termination equals

320 - (byte value 20).

0x62

0x63

0f

∆t step

Hold-off time

00

b5

320s hold-off

The hold-off time is 320 - (byte value 20).

Must be equal to 0xb5.

EEPROM check 2 0x64

181

NA

Reserved

0x65 0x7f

Not currently used by the bq2040.

Note:

1. Can be adjusted to calibrate the battery pack.

25

bq2040

Table 11. Example Register Contents (String Data)

0x

X1

0x

X2

0x

X3

0x

X4

0x

X5

0x

X6

0x

X7

0x

X8

0x

X9

0x

Xa

0x

Xb

String Description

Address X0

0x20-

09

42

B

45

E

4e

N

43

C

48

H

4d

M

41

A

52

R

51

Q

Manufacturer name

-

0x2b

0x30-

06

42

B

51

Q

32

2

30

0

34

4

30

0

Device name

-

0x37

0x40-

04

6c

L

69

I

4f

O

4e

N

Device chemistry

Manufacturer data

-

0x45

0x50-

05

42

B

51

Q

32

2

30

0

32

2

0x55

26

bq2040

Absolute Maximum Ratings

Symbol

V_CC

Parameter

Relative to V_SS

Minimum

-0.3

Maximum

+7.0

Unit

V

Notes

All other pins

REF

-0.3

+7.0

V

-0.3

+8.5

V

Current limited by R11 (see Figure 1)

Minimum 100Ω series resistor should

be used to protect SR in case of a

shorted battery.

V_SR

Relative to V_SS

-0.3

0

+7.0

+70

V

Operating tempera-

ture

T_OPR

°C

Commercial

Note:

Permanent device damage may occur if Absolute Maximum Ratings are exceeded. Functional opera-

tion should be limited to the Recommended DC Operating Conditions detailed in this data sheet. Expo-

sure to conditions beyond the operational limits for extended periods of time may affect device reliability.

DC Voltage Thresholds (T = T

; V = 3.0 to 5.5V)

OPR

A

Symbol

Parameter

Battery voltage error relative to SB

Minimum

Typical

Maximum

Unit

Notes

See note

E_VSB

-50mV

-

50mV

V

Note:

The accuracy of the voltage measurement may be improved by adjusting the battery voltage offset and

gain, stored in external EEPROM. For best operation, V_CCshould be 1.5V greater than V_SB

.

27

bq2040

Recommended DC Operating Conditions (T = T

)

A

OPR

Symbol

Parameter

Supply voltage

Minimum Typical Maximum

Unit

Notes

V_CCexcursion from < 2.0V to ≥

3.0V initializes the unit.

V_CC

3.0

4.25

6.5

V

Reference at 25°C

5.7

4.5

2.0

-

6.0

6.3

7.5

-

V

I_REF= 5µA

V_REF

R_REF

Reference at -40°C to +85°C

Reference input impedance

-

5.0

90

120

170

-

MΩ V_REF= 3V

µA

_CC= 3.0V

135

180

250

V_CC

-

V

I_CC

Normal operation

-

µA V_CC= 4.25V

µA V_CC= 5.5V

V

-

V_SB

Battery input

0

R_SBmax

I_DISP

SB input impedance

DISP input leakage

V_OUToutput leakage

10

-

MΩ 0 < V_SB< V_CC

µA V_DISP= V_SS

µA EEPROM off

-

5

I_LVOUT

-0.2

-

0.2

V_SR< V_SS= discharge;

V_SR> V_SS= charge

V_SR

R_SR

Sense resistor input

SR input impedance

-0.3

-

2.0

V

10

-

V_CC

MΩ -200mV < V_SR< V_CC

V

ESCL, ESDA

0.5 V_CC

V_IH

V_IL

Logic input high

Logic input low

1.4

0

5.5

SMBC, SMBD

V

ESCL, ESDA

0.3 V_CC

0.6

-0.5

-

V

SMBC, SMBD

V_OL

I_OL

Data, clock output low

Sink current

-

0.4

V

I_OL=350µA, SMBC, SMBD

100

350

µA

V

_OL≤0.4V, SMBC, SMBD

V_CC= 3V, I_OLS≤ 1.75mA

V_OLSL

V_OLSH

LED_Xoutput low, low V_CC

LED_Xoutput low, high V_CC

-

0.1

0.4

-

V

LED₁–LED₄

V_CC= 6.5V, I_OLS≤ 11.0mA

LED₁–LED₄

V_OHVL

V_OHVH

I_VOUT

I_OLS

V_OUToutput, low V_CC

V_OUToutput, high V_CC

V_OUTsource current

LED_Xsink current

V_CC- 0.3

V_CC- 0.6

-33

-

V

V_CC= 3V, I_VOUT= -5.25mA

V_CC= 6.5V, I_VOUT= -33.0mA

mA At V_OHVH= V_CC- 0.6V

mA At V_OLSH= 0.4V

11.0

Note:

All voltages relative to V_SS.

28

bq2040

AC Specifications

Symbol

F_SMB

Parameter

Min

Max

Units

Notes

SMBus operating frequency

10

100

KHz

Bus free time between stop and

start condition

µs

T_BUF

4.7

4.0

Hold time after (repeated) start

condition

T_HD:STA

T_SU:STA

T_SU:STO

T_HD:DAT

T_SU:DAT

T_LOW

Repeated start condition setup time

Stop condition setup time

Data hold time

4.7

4.0

300

250

4.7

4.0

µs

ns

µs

ns

Data setup time

Clock low period

T_HIGH

T_F

Clock high period

Clock/data fall time

Clock/data rise time

300

T_R

1000

Cumulative clock low extend time

(slave)

T_LOW:SEXT

T_TIMEOUT

25

35

ms

25

Bus Timing Data

t_R

t_F

t_HIGH

t_SU:STA

SMBC

t_HD:STA

t_LOW

t_HD:DAT

t_SU:DAT

t_SU:STO

SMBD

t_BUF

TD294501.eps

29

bq2040

16-Pin SOIC Narrow (SN)

(

)

16-Pin SN SOIC Narrow

Dimension

Minimum

0.060

0.004

0.013

0.007

0.385

0.150

0.045

0.225

0.015

Maximum

0.070

0.010

0.020

0.010

0.400

0.160

0.055

0.245

0.035

A

A1

B

D

B

e

C

D

E

e

H

L

H

All dimensions are in inches.

A

C

A1

.004

L

30

bq2040

Data Sheet Revision History

ChangeNo.

Page No.

Description of Change

Updated recommended application schematic.

3

9

Changed overcurrent fault conditon for ChargingCurrent < 1024mA.

4Hz operation of LED clarification.

10

11

14

Added descriptions for bits 7 and 13 of BatteryMode.

AtRateTimeToEmpty and AtRateTimeToFull invalid data indication correction.

RunTimeToEmpty, AverageTimeToEmpty and AverageTimeToFull invalid data

indication corrections.

3

15, 16

3

4

23

24

25

6

Changed typical Battery low % value for Li-Ion with EDV1 = 3.0V/cell.

Li-Ion taper current is stored in 2’s complement.

Changed typical ∆T step and Full-charge percentage for Li-Ion.

Voltage gain is (R4 + R5)/R4.

Changed typical EDV1 and EDVF values for Li-Ion.

Added V_SBshould not exceed 2.4V

8

The self discharge rate approximately doubles or halves

Changed cycle count increase from 30 to 32 for condition request.

Changed AtRateOK() indication from EDV1 to EDVF

Changed self-discharge programming from 52.75/x to 52.73/x.

Changed recommended EDVF charging current from 0mA to 100mA

11

14

25

Notes:

Changes 1 and 2 refer to the 1998 Data Book

Change 3 = June1998 D changes from Jan. 1998 C.

Change 4 = June 1999 E changes from June 1998 D.

Ordering Information

bq2040

Temperature Range:

blank = Commercial (0 to 70°C)

Package Option:

SN = 16-pin narrow SOIC

Device:

bq2040 Gas Gauge IC With SMBus Interface

31

PACKAGE OPTION ADDENDUM

www.ti.com

8-Mar-2005

PACKAGING INFORMATION

Orderable Device

Status ⁽¹⁾

Package Package

Pins Package Eco Plan ⁽²⁾Lead/Ball Finish MSL Peak Temp ⁽³⁾

Qty

Type

SOIC

Drawing

BQ2040SN-C408

BQ2040SN-C408TR

BQ2040SN-D111

NRND

D

16

40

None

CU NIPDAU Level-1-220C-UNLIM

2500

40

ACTIVE

PREVIEW

BQ2040SN-D111TR

BQ2040SN-D111TRG4

2500

Call TI

⁽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 - May not be currently available - please check http://www.ti.com/productcontent for the latest availability information and additional

product content details.

None: Not yet available Lead (Pb-Free).

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.

Green (RoHS & no Sb/Br): TI defines "Green" to mean "Pb-Free" and in addition, uses package materials that do not contain halogens,

including bromine (Br) or antimony (Sb) above 0.1% of total product weight.

(3)

MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDECindustry standard classifications, and peak solder

temperature.

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 1

IMPORTANT NOTICE

Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications,

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型号:	BQ2040SN-C408
Brand Name：	Texas Instruments
是否无铅：	不含铅
是否Rohs认证：	符合
生命周期：	Active
零件包装代码：	SOIC
包装说明：	SOP,
针数：	16
Reach Compliance Code：	compliant
ECCN代码：	EAR99
HTS代码：	8542.39.00.01
风险等级：	1.31
可调阈值：	YES
模拟集成电路 - 其他类型：	POWER SUPPLY SUPPORT CIRCUIT
JESD-30 代码：	R-PDSO-G16
JESD-609代码：	e4
长度：	9.9 mm
湿度敏感等级：	2
信道数量：	1
功能数量：	1
端子数量：	16
最高工作温度：	70 °C
最低工作温度：
封装主体材料：	PLASTIC/EPOXY
封装代码：	SOP
封装形状：	RECTANGULAR
封装形式：	SMALL OUTLINE
峰值回流温度（摄氏度）：	260
认证状态：	Not Qualified
座面最大高度：	1.75 mm
最大供电电压 (Vsup)：	6.5 V
最小供电电压 (Vsup)：	3 V
标称供电电压 (Vsup)：	4.25 V
表面贴装：	YES
温度等级：	COMMERCIAL
端子面层：	Nickel/Palladium/Gold (Ni/Pd/Au)
端子形式：	GULL WING
端子节距：	1.27 mm
端子位置：	DUAL
处于峰值回流温度下的最长时间：	NOT SPECIFIED
宽度：	3.9 mm
Base Number Matches：	1

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