General Description

The MAX1908/MAX8724/MAX8765 highly integrated, multi-

chemistry battery-charger control ICs simplify the construc-

tion of accurate and efficient chargers. These devices use

analog inputs to control charge current and voltage, and

can be programmed by the host or hardwired. The

MAX1908/MAX8724/MAX8765 achieve high efficiency

using a buck topology with synchronous rectification.

The MAX1908/MAX8724/MAX8765 feature input current

limiting. This feature reduces battery charge current when

the input current limit is reached to avoid overloading the

AC adapter when supplying the load and the battery

charger simultaneously. The MAX1908/MAX8724/

MAX8765 provide outputs to monitor current drawn from

the AC adapter (DC input source), battery-charging cur-

rent, and the presence of an AC adapter. The MAX1908’s

conditioning charge feature provides 300mA to safely

charge deeply discharged lithium-ion (Li+) battery packs.

The MAX1908 includes a conditioning charge feature

while the MAX8724/MAX8765 do not.

The MAX1908/MAX8724/MAX8765 charge two to four

series Li+ cells, providing more than 5A, and are avail-

able in a space-saving, 28-pin, thin QFN package (5mm

× 5mm). An evaluation kit is available to speed designs.

Applications

Notebook and Subnotebook Computers

Personal Digital Assistants

Handheld Terminals

Features

♦ ±0.5% Output Voltage Accuracy Using Internal

Reference (0°C to +85°C)

♦ ±4% Accurate Input Current Limiting

♦ ±5% Accurate Charge Current

♦ Analog Inputs Control Charge Current and

Charge Voltage

♦ Outputs for Monitoring

Current Drawn from AC Adapter

Charging Current

AC Adapter Presence

♦ Up to 17.6V Battery-Voltage Set Point

♦ Maximum 28V Input Voltage

♦ > 95% Efficiency

♦ Shutdown Control Input

♦ Charge Any Battery Chemistry

Li+, NiCd, NiMH, Lead Acid, etc.

Low-Cost Multichemistry Battery Chargers

________________________________________________________________ Maxim Integrated Products

1

28

27

26

25

24

23

22

IINP

CSSP

CSSN

DHI

BST

LX

DLOV

8

9

10

11

12

13

14

SHDN

ICHG

ACIN

ACOK

REFIN

ICTL

GND

15

16

17

18

19

20

21

7

6

5

4

3

2

1

MAX1908

MAX8724

MAX8765

THIN QFN

TOP VIEW

Pin Configuration

Ordering Information

MAX1908

MAX8724

MAX8765

AC ADAPTER

INPUT

TO EXTERNAL

LOAD

LDO

FROM HOST

μP

10

μH

0.015

Ω

BATT+

DCIN

REFIN

VCTL

ICTL

ACIN

ACOK

SHDN

ICHG

IINP

CCV

CCI

CCS

CELLS

LDO

BST

DLOV

DHI

LX

DLO

PGND

CSIP

CSIN

BATT

REF

CLS

GND

CSSP

CSSN

0.01

Ω

Minimum Operating Circuit

19-2764; Rev 4; 7/05

For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at

1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.

EVALUATION

KIT

AVAILABLE

PART

TEMP RANGE

PIN-

PACKAGE

PKG CODE

MAX1908ETI

-40°C to +85°C

28 Thin QFN

T2855-6

MAX8724ETI

-40°C to +85°C

28 Thin QFN

T2855-6

MAX8765ETI

-40°C to +85°C

28 Thin QFN

T2855-6