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General Description

The MAX1666 provides complete protection against over-

voltage, undervoltage, overcharge current, overdischarge

current, and cell mismatch for 2-cell to 4-cell Lithium-Ion

battery packs. The voltage of each cell in the battery pack

is checked and compared to the programmable threshold

and to the other cells in the pack.

The MAX1666 protects the battery pack in an overcurrent

condition by disconnecting the pack from the load at a pro-

grammable limit. On-chip power MOSFET drivers control

external P-channel MOSFETs to disconnect the cells from

external terminals when faults occur.

The MAX1666 employs a unique timing scheme that allows

three modes of operation, for optimal performance and bat-

tery power conservation. The MAX1666 can operate in a

stand-alone configuration or in conjunction with a micro-

controller. It is available in three versions: the “S” version

monitors two Li-Ion cells, the “V” version monitors three

cells, and the “X” version monitors four cells.

Applications

2/3/4-Cell Lithium-Ion Battery Pack

Features

o Overvoltage Protection

Programmable Limits from +4.0V to +4.4V

Accurate to ±0.5%

o Undervoltage Protection

Programmable Limits from +2.0V to +3.0V

Accurate to ±2.5%

o Cell Mismatch Protection

Programmable Limits from 0 to 500mV

Accurate to ±10%

o Overcharge Current Protection

o Overdischarge Current Protection

o Low Operating Supply Current: 30µA typ

o Low Standby Current: 1µA max

o +28V max Input Voltage

o Available in Small 16-Pin QSOP (MAX1666S) and

20-Pin QSOP (MAX1666V/X) Packages

Advanced Lithium-Ion

Battery-Pack Protector

________________________________________________________________

Maxim Integrated Products

1

TOP VIEW

20

19

18

17

16

15

14

13

1

2

3

4

5

6

7

8

UVO

REF

OVA

CGO

TKO

DSO

SRC

UVA

MMA

WRN

PKF

B1P

B2P

B3P

B3P

12

11

9

10

CGI

DSI

PKN

GND

MAX1666V

20

19

18

17

16

15

14

13

1

2

3

4

5

6

7

8

UVO

REF

OVA

CGO

TKO

DSO

SRC

UVA

MMA

WRN

PKF

B1P

B2P

B3P

B4P

12

11

9

10

CGI

DSI

PKN

GND

MAX1666X

16

15

14

13

12

11

10

9

1

2

3

4

5

6

7

8

SRC

REF

OVA

UVA

MMA

PKF

CGI

DSI

MAX1666S

DSO

TKO

BIP

CGO

B2P

GND

PKN

QSOP

QSOP

QSOP

19-1465; Rev 1; 7/99

PART

MAX1666SEEE

MAX1666VEEP

MAX1666XEEP

-40°C to +85°C

-40°C to +85°C

-40°C to +85°C

TEMP. RANGE

PIN-PACKAGE

16 QSOP

20 QSOP

20 QSOP

Pin Configurations

Ordering Information

Selector Guide

Typical Operating Circuits appear at end of data sheet.

NUMBER OF LI-ION CELLS

PART

MAX1666S

2

3

4

MAX1666X

MAX1666V