TEXAS INSTRUMENTS bq2002D, bq2002T Technical data

bq2002D/T

NiCd/NiMH Fast-Charge Management ICs

Features

Fast charge of nickel cadmium

➤

or nickel-metal hydride batter
ies

Direct LED output displays

➤

charge status
Fast-charge termination by

➤

rate of rise of temperature,
maximum voltage, maximum
temperature, and maximum
time

Internal band-gap voltage ref

➤

erence
Optional top-off charge (bq2002T

➤

only)

➤ Selectable pulse-trickle charge

rates (bq2002T only)

➤ Low-power mode
➤ 8-pin 300-mil DIP or 150-mil

SOIC

Pin Connections

TM

LED

BAT
V

1

2

3

4

SS

8

CC

7

INH

V

6

CC

TS

5

General Description

The bq2002D/T Fast-Charge IC are
low-cost CMOS battery-chargecontrol

­lers able to provide reliable charge ter
mination for both NiCd and NiMH bat
tery applications. Controlling a
current-limited or constant-current
supply allows the bq2002D/T to be the
basis for a cost-effective stand-alone or
system-integrated charger. The
bq2002D/T integrates fast charge with
optional top-off and pulsed-trickle con
trol in a single IC for charging one or

-

more NiCd or NiMH battery cells.
Fast charge is initiated on application

of the charging supply or battery re
placement. For safety, fast charge is
inhibited if the battery temperature
and voltage are outside configured
limits.

Pin Names

TM Timer mode select input
LED
BAT Battery voltage input
V

SS

Charging status output

System ground

Fast charge is terminated by any of
the following:

Rate of temperature rise

n

-

-

Maximum voltage

n

­Maximum temperature

n

Maximum time

n

After fast charge, the bq2002T option
ally tops-off and pulse-trickles the
battery per the pre-configured limits.

-

Fast charge may be inhibited using
the INH pin. The bq2002D/T may be
placed in low-standby-power mode to
reduce system power consumption.

-

TS Temperature sense input
V

CC

Supply voltage input
INH Charge inhibit input
CC Charge control output

-

8-Pin DIP or

Narrow SOIC

PN-200201.eps

bq2002D/T Selection Guide

Part No. TCO HTF LTF Fast Charge Time-Out Top-Off Maintenance

C/4 440 min None None

bq2002D

bq2002T

SLUS133B–JULY 2000

0.225 ∗ V

0.225 ∗ V

CC

CC

0.25 ∗ V

0.25 ∗ V

CC

CC

None

0.4 ∗ V

CC

1C 110 min None None
2C 55 min None None

C/4 320 min C/64 C/256

1C 80 min C/16 C/256
2C 40 min None C/128

1

bq2002D/T

Pin Descriptions

TM

LED

BAT

V

SS

TS

V

CC

INH

Timer mode input

A three-level input that controls the settings
for the fast charge safety timer, voltage ter
mination mode, top-off, pulse-trickle, and
voltage hold-off time.

Charging output status

Open-drain output that indicates the charging
status.

Battery input voltage

The battery voltage sense input. The input
to this pin is created by a high-impedance re
sistor divider network connected between
the positive and negative terminals of the
battery.

System ground
T emperaturesenseinput

Input for an external battery temperature
monitoring thermistor.

Supply voltage input

5.0V±20% power input.

Charge inhibit input

When high, INH suspends the fast charge in
progress. When returned low, the IC re

sumes operation at the point where initially
suspended.

CC

-

Charge control output

An open-drain output used to control the
charging current to the battery. CC switch
ing to high impedance (Z) enables charging
current to flow, and low to inhibit charging
current. CC is modulated to provide top-off,
if enabled, and pulse trickle.

Functional Description

Figures 2 and 3 show state diagrams of bq2002D/T and
Figure 4 shows the block diagram of the bq2002D/T.

-

Battery Voltageand Temperature
Measurements

Battery voltage and temperature are monitored for
maximum allowable values. The voltage presented on
the battery sense input, BAT, should represent a
single-cell potential for the battery under charge. A
resistor-dividerratioof

RB1

=N-1

RB2

is recommended to maintain the battery voltage within
the valid range, where N is the number of cells, RB1 is
the resistor connected to the positive battery terminal,
and RB2 is the resistor connected to the negative bat­tery terminal. See Figure 1.

-

-

V

CC

RT1

RB1

BAT

bq2002D/T

V

SS

RB2

BAT pin connection Thermistor connection

R3

R4

Mid-level

V

CC

TM

T

bq2002D/T

V

SS

S

RT2

PACK +

N
T
C

setting for TM

NTC = negative temperature coefficient thermistor.

F2002DT1.eps

Figure 1. Voltage and Temperature Monitoring and TM Pin Configuration

2

bq2002D/T

Chip on

4.0V

V

CC

Fast Charge,

CC = Z

LED = Low

V

Top-off

LED = Z

V

CC

Chip on

CC

> 0.25V

V

TS

0.25 VCC < VTS < 0.6 V

( T/ t or
Maximum Time Out)
and TM = High

V

> 2V or

BAT

VTS < 0.225 VCC or
Maximum Time Out

Battery Voltage

V

BAT

too High?

< 2V

V

BAT

>

2V

Battery

Temperature?

V
V

BAT
TS

< 0.25V

V

TS

< 2V and

> 0.25V

V

T/ t or

V

> 2V or

BAT

< 0.25V

V

TS

Maximum Time Out

V

or

CC

Figure 2. bq2002D State Diagram

4.0V

Fast

LED =

Low

Battery Voltage

too High?

< 2V

V

BAT

CC

V

BAT

VTS < 0.225 VCC or
(( T/ t or
Maximum Time Out)
and TM = High)

Battery

Temperature?

> 2V or

V

VTS > 0.6 VCC or
VTS < 0.25 V

V

BAT

VTS < 0.6 VCC and
VTS > 0.25 V

V

CC

BAT

< 2V and

CC

Off,

CC = Low

LED = Low

Off,

CC = Low

LED = Z

2V

>

Charge
Pending

V

BAT

V

CC

CC

> 2V

BAT

Trickle
LED =

Low

Trickle

LED = Z

2V

SD2002D.eps

Charge

Pending

V

BAT

V

> 2V

BAT

2V

SD2002T.eps

Figure 3. bq2002T State Diagram

3

bq2002D/T

OSC

Clock

Phase

Generator

TM

INH

Charge-Control

State Machine

Power-On

Reset

CC

Timing

Control

LED

Figure 4. Block Diagram

Note: This resistor-divider network input impedance to
end-to-end should be at least 200kΩ and less than 1 MΩ.

A ground-referenced negative temperature coefficient ther
mistor placed in proximity to the battery may be used as a
low-cost temperature-to-voltage transducer. The tempera
ture sense voltage input at TS is developed using a
resistor-thermistor network between V

and VSS. See

CC

Figure 1.

Starting A Charge Cycle

Either of two events starts a charge cycle (see Figure 5):

1. Application of power to V

2. Voltage at the BAT pin falling through the maximum
cell voltage where

V

If the battery is within the configured temperature and
voltage limits, the IC begins fast charge. The valid bat
tery voltage range is V
ture range is V
V

HTF<VTS

HTF<VTS<VLTF

for the bq2002D where

V

LTF

V

= 0.25 ∗ VCC±5% (bq2002T only)

HTF

or

CC

=2V±5%

MCV

BAT<VMCV

= 0.4 ∗ VCC±5%

. The valid tempera

for the bq2002T and

Sample

History

T/ t

ALU

MCV

Check

BAT

Power

Down

Voltage

Reference

A to D

Converter

V

CC

HTF/

LTF

Check

TCO

Check

V

SS

TS

Bd2002TD.eps

If the battery voltage or temperature is outside of these
limits, the IC pulse-trickle charges until the tempera­ture falls within the allowed fast charge range or a new

-

charge cycle is started.
Fast charge continues until termination by one or more of

­the four possible termination conditions:

n

Rate of temperature rise

n

Maximum voltage

n

Maximum temperature

n

Maximum time

T/ t Termination

The bq2002D/T samples at the voltage at the TS pin ev
ery 19s and compares it to the value measured three
samples earlier. If the voltage has fallen 25.6mV or
more, fast charge is terminated. The ∆T/∆t termination

-

test is valid only when V

-

bq2002T and V

TCO<VTS

TCO<VTS<VLTF

for the bq2002D.

Temperature Sampling

A sample is taken by averaging together 16 measure
ments taken 57µs apart. The resulting sample period
(18.18ms) filters out harmonics around 55Hz. This tech

-

for the

-

-

4

bq2002D/T

Fast ChargingVCC = 0

CC Output

Charge initiated by application of power

LED

Top-Off

(optional,

bq2002T only)

286

4576

Figure 5. Charge Cycle Phases

nique minimizes the effect of any AC line ripple that
may feed through the power supply from either 50Hz or
60Hz AC sources. Tolerance on all timing is ±20%.

Maximum Voltage,Temperature,and Time

Any time the voltage on the BAT pin exceeds the maxi­mum cell voltage, V

, fast charge or optional top-off

MCV

charge is terminated.

Table 1. Fast-Charge Safety Time/Top-Off Table

Pulse-Trickle

See

Table 1

286

s

s

s

Charge initiated by battery replacement

Fast Charging

(optional,

bq2002T only)

TD2002F1.eps

Maximum temperature termination occurs anytime the
voltage on the TS pin falls below the temperature cut-off
threshold V

TCO

where

V

= 0.225 ∗ VCC±5%

TCO

Maximum charge time is configured using the TM pin.
Time settings are available for corresponding charge
rates of C/4, 1C, and 2C. Maximum time-out termina­tion is enforced on the fast-charge phase, then reset, and

Typical Fast-Charge

and Top-Off

Part No.

Corresponding

Fast-Charge Rate TM

Time Limits

C/4 Mid 440 None None None

bq2002D

1C Low 110 None None None
2C High 55 None None None

C/4 Mid 320 C/64 C/256 18.3

bq2002T

1C Low 80 C/16 C/256 73.1
2C High 40 None C/128 73.1

Notes: Typical conditions = 25°C, VCC= 5.0V

Mid = 0.5*V

CC

±0.5V

Tolerance on all timing is ±20%

(minutes)

Pulse-

Top-Off

Rate

Pulse-

Trickle Rate

Trickle

Period (ms)

5

bq2002D/T

enforced again on the top-off phase, if selected (bq2002T
only). There is no time limit on the trickle-charge
phase.

Top-off Charge—bq2002T Only

An optional top-off charge phase may be selected to
follow fast charge termination for 1C and C/4 rates.
This phase may be necessary on NiMH or other bat
tery chemistries that have a tendency to terminate
charge prior to reaching full capacity. With top-off en
abled, charging continues at a reduced rate after
fast-charge termination for a period of time selected
by the TM pin. (See Table 1.) During top-off, the CC
pin is modulated at a duty cycle of 286µs active for
every 4290µs inactive. This modulation results in an
average rate 1/16th that of the fast charge rate. Maxi
mum voltage, time, and temperature are the only ter
mination methods enabled during top-off.

Pulse-TrickleCharge—bq2002T Only

Pulse-trickle is used to compensate for self-discharge
while the battery is idle in the charger. The battery is
pulse-trickle charged by driving the CC pin active for a
period of 286µs for every 72.9ms of inactivity for 1C and
2C selections, and 286µs for every 17.9ms of inactivity
for C/4 selection. This results in a trickle rate of C/256
for the top-off enabled mode and C/128 otherwise.

TM Pin

The TM pin is a three-level pin used to select the
charge timer, top-off, voltage termination mode,
trickle rate, and voltage hold-off period options. Table
1 describes the states selected by the TM pin. The
mid-level selection input is developed by a resistor
divider between V
on TM at V

/2 ± 0.5V. See Figure 5.

CC

and ground that fixes the voltage

CC

Charge Status Indication

In the fast charge and charge pending states, and when
ever the inhibit pin is active, the LED
LED

pin is driven to the high-Z state for all other condi
tions. Figure 3 outlines the state of the LED
charge.

-

Charge Inhibit

Fast charge and top-off may be inhibited by using the

­INH pin. When high, INH suspends all fast charge and
top-off activity and the internal charge timer. INH
freezes the current state of LED
moved. Temperature monitoring is not affected by the
INH pin. During charge inhibit, the bq2002D/T contin
ues to pulse-trickle charge the battery per the TM selec

­tion. When INH returns low, charge control and the

­charge timer resume from the point where INH became

active. The V

sample history is cleared by INH.

TS

pin goes low. The

pin during

until inhibit is re

Low-Power Mode

The IC enters a low-power state when V
above the power-downthreshold(V

V

PD=VCC

Both the CC pin and the LED
high-Z state. The operating current is reduced to less
than 1µA in this mode. When V
below V
new charge cycle begins.

, the IC pulse-trickle charges until the next

PD

PD

- (1V ±0.5V)
pin are driven to the

BAT

BAT

) where

returns to a value

-

-

-

-

-

is driven

6

bq2002D/T

Absolute Maximum Ratings

Symbol Parameter Minimum Maximum Unit Notes

V

CC

V

T

T

OPR

T

STG

T

SOLDER

T

BIAS

VCCrelative to V

SS

DC voltage applied on any pin
excluding V

relative to V

CC

SS

-0.3 +7.0 V

-0.3 +7.0 V

Operating ambient temperature 0 +70 °C Commercial
Storage temperature -40 +85 °C
Soldering temperature - +260 °C 10s max.
Temperature under bias -40 +85 °C

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 Thresholds (T

= 0 to 70°C; V

A

CC

20%)

±

Symbol Parameter Rating Tolerance Unit Notes

V

V

V

V

V

TCO

HTF

LTF

MCV

Temperature cutoff

High-temperature fault

Low-temperature fault

0.225*V

0.25 ∗ V

0.4 ∗ V

CC

CC

CC

±5%

±5%

±5%

Maximum cell voltage 2 ±5% V

TS

V

and top-off

V

VTS≤ V
V

TS

V

(bq2002T only)
V

BAT

charge

≤ V

≥ V

terminates fast charge

TCO

inhibits fast charge start

HTF

inhibits fast charge start

LTF

≥ V

inhibits/terminates fast

MCV

-

-

7

bq2002D/T

Recommended DC Operating Conditions (T

= 0 to 70°C)

A

Symbol Condition Minimum Typical Maximum Unit Notes

V

CC

V

BAT

V

TS

Supply voltage 4.0 5.0 6.0 V
Battery input 0 - V
Thermistor input 0.5 - V

CC

CC

V
VVTS< 0.5V prohibited

Logic input high 0.5 - - V INH

V

IH

V

IM

Logic input high V

Logic input mid

- 0.5 - - V TM

CC

V

CC

- 0.5

2

-

V

CC

05+ .

2

VTM

Logic input low - - 0.1 V INH

V

IL

Logic input low - - 0.5 V TM

V

OL

V

PD

Logic output low - - 0.8 V LED,CC, IOL= 10mA

max. powers

V

V

≥

BAT

PD

BAT<VPD

min. =

Power down

- 1.5

V

CC

-

VCC- 0.5

down bq2002D/T;

V

V
normal operation.

Outputs unloaded,

A

I

CC

I

SB

Supply current - - 500

Standby current - - 1

µ

V

= 5.1V

CC

AVCC= 5.1V,V

µ

BAT=VPD

I

OL

I

L

I

OZ

LED, CC sink 10 - - mA @VOL=VSS+ 0.8V
Input leakage - ­Output leakage in

high-Z state

Note: All voltages relative to VSS.

-5 - -

8

1

±

A INH, CC,V=VSSto V

µ

A

µ

LED

,CC

CC

bq2002D/T

Impedance

Symbol Parameter Minimum Typical Maximum Unit

R

BAT

R

TS

Battery input impedance 50 - - M
TS input impedance 50 - - M

Ω

Ω

Timing (T

Symbol Parameter Minimum Typical Maximum Unit Notes

d

FCV

Note: Typical is at TA= 25°C, VCC= 5.0V.

= 0 to +70°C; V

A

Time-base variation -20 - 20 %

CC

10%)

±

9

bq2002D/T

8-Pin DIP(PN

E1

E

e

)

D

L

C

8-Pin SOIC Narrow (SN)

8-Pin PN(0.300" DIP

Dimension

A 0.160 0.180 4.06 4.57

A1 0.015 0.040 0.38 1.02

B 0.015 0.022 0.38 0.56

B1 0.055 0.065 1.40 1.65

A

A1

S

B1

B

G

C 0.008 0.013 0.20 0.33
D 0.350 0.380 8.89 9.65
E 0.300 0.325 7.62 8.26

E1 0.230 0.280 5.84 7.11

e 0.300 0.370 7.62 9.40
G 0.090 0.110 2.29 2.79
L 0.115 0.150 2.92 3.81

S 0.020 0.040 0.51 1.02

Min. Max. Min. Max.

)

Inches Millimeters

10

8-Pin SN(0.150" SOIC

Inches Millimeters

Dimension

A 0.060 0.070 1.52 1.78

A1 0.004 0.010 0.10 0.25

B 0.013 0.020 0.33 0.51
C 0.007 0.010 0.18 0.25
D 0.185 0.200 4.70 5.08
E 0.150 0.160 3.81 4.06

e 0.045 0.055 1.14 1.40
H 0.225 0.245 5.72 6.22
L 0.015 0.035 0.38 0.89

Min. Max. Min. Max.

)

bq2002D/T

Data Sheet Revision History

Change No. Page No. Description Nature of Change

13

1 5 Added top-off values.

2 All Revisedand expanded this data sheet
3 All Revisedand included bq2002D Addition of device
4 Specified package information for the bq2002D

51,5

Notes: Change 1 = Sept. 1996 B changes from Aug. 1994.

Ordering Information

Was: Table 1 gave the bq2002D/T Operational Summary.
Is: Figure 2 gives the bq2002D/T Operational Summary.

Corrected transposed rows in Selection Guide Table and
made Table 1 consistent with Selection Guide.

Changed table to figure.

Added column and val
ues.

-

bq2002

Package Option:

PN = 8-pin plastic DIP
SN = 8-pin narrow SOIC*

Device:

D = bq2002D Fast-Charge IC
T = bq2002T Fast-Charge IC

* bq2002D is only available in the 8-pin narrow SOIC
package

11

PACKAGE OPTION ADDENDUM

www.ti.com

30-Mar-2005

PACKAGING INFORMATION

Orderable Device Status

(1)

Package

Type

Package
Drawing

Pins Package

Qty

Eco Plan

BQ2002DSN ACTIVE SOIC D 8 75 Pb-Free

BQ2002DSNTR ACTIVE SOIC D 8 2500 Pb-Free

BQ2002TPN ACTIVE PDIP P 8 50 Pb-Free

BQ2002TPNE4 ACTIVE PDIP P 8 50 Pb-Free

BQ2002TSN ACTIVE SOIC D 8 75 Pb-Free

BQ2002TSNTR ACTIVE SOIC D 8 2500 Pb-Free

(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.

(RoHS)

(RoHS)

(RoHS)

(RoHS)

(RoHS)

(RoHS)

(2)

Lead/Ball Finish MSL Peak Temp

CU NIPDAU Level-2-260C-1YEAR/

Level-1-220C-UNLIM

CU NIPDAU Level-2-260C-1YEAR/

Level-1-220C-UNLIM

CU NIPDAU Level-NC-NC-NC

CU NIPDAU Level-NC-NC-NC

CU NIPDAU Level-2-260C-1YEAR/

Level-1-220C-UNLIM

CU NIPDAU Level-2-260C-1YEAR/

Level-1-220C-UNLIM

(3)

(2)

Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS) or Green (RoHS & no Sb/Br) - please check

http://www.ti.com/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.
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.

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,
enhancements, improvements, and other changes to its products and services at any time and to discontinue
any product or service without notice. Customers should obtain the latest relevant information before placing
orders and should verify that such information is current and complete. All products are sold subject to TI’s terms
and conditions of sale supplied at the time of order acknowledgment.

TI warrants performance of its hardware products to the specifications applicable at the time of sale in
accordance with TI’s standard warranty. Testing and other quality control techniques are used to the extent TI
deems necessary to support this warranty . Except where mandated by government requirements, testing of all
parameters of each product is not necessarily performed.

TI assumes no liability for applications assistance or customer product design. Customers are responsible for
their products and applications using TI components. To minimize the risks associated with customer products
and applications, customers should provide adequate design and operating safeguards.

TI does not warrant or represent that any license, either express or implied, is granted under any TI patent right,
copyright, mask work right, or other TI intellectual property right relating to any combination, machine, or process
in which TI products or services are used. Information published by TI regarding third-party products or services
does not constitute a license from TI to use such products or services or a warranty or endorsement thereof.
Use of such information may require a license from a third party under the patents or other intellectual property
of the third party, or a license from TI under the patents or other intellectual property of TI.

Reproduction of information in TI data books or data sheets is permissible only if reproduction is without
alteration and is accompanied by all associated warranties, conditions, limitations, and notices. Reproduction
of this information with alteration is an unfair and deceptive business practice. TI is not responsible or liable for
such altered documentation.

Resale of TI products or services with statements different from or beyond the parameters stated by TI for that
product or service voids all express and any implied warranties for the associated TI product or service and
is an unfair and deceptive business practice. TI is not responsible or liable for any such statements.

Following are URLs where you can obtain information on other Texas Instruments products and application
solutions:

Products Applications

Amplifiers amplifier.ti.com Audio www.ti.com/audio
Data Converters dataconverter.ti.com Automotive www.ti.com/automotive

DSP dsp.ti.com Broadband www.ti.com/broadband
Interface interface.ti.com Digital Control www.ti.com/digitalcontrol
Logic logic.ti.com Military www.ti.com/military
Power Mgmt power.ti.com Optical Networking www.ti.com/opticalnetwork
Microcontrollers microcontroller.ti.com Security www.ti.com/security

Telephony www.ti.com/telephony
Video & Imaging www.ti.com/video
Wireless www.ti.com/wireless

Mailing Address: Texas Instruments

Post Office Box 655303 Dallas, Texas 75265

Copyright  2005, Texas Instruments Incorporated