General Description

The MAX1908/MAX8724 highly integrated, multichemistry

battery-charger control ICs simplify the construction of

accurate and efficient chargers. These devices use ana-

log inputs to control charge current and voltage, and can

be programmed by the host or hardwired. The MAX1908/

MAX8724 achieve high efficiency using a buck topology

with synchronous rectification.

The MAX1908/MAX8724 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 provide outputs

to monitor current drawn from the AC adapter (DC input

source), battery-charging current, and the presence of

an AC adapter. The MAX1908’s conditioning charge fea-

ture provides 300mA to safely charge deeply discharged

lithium-ion (Li+) battery packs.

The MAX1908 includes a conditioning charge feature

while the MAX8724 does not.

The MAX1908/MAX8724 charge two to four series Li+

cells, providing more than 5A, and are available 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

Hand-Held 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

♦ Charges 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

89

10

11

12

13

14

15

16

17

18

19

20

21

VCTL

BATT

CELLS

CSIN

CSIP

PGND

DLO

7

6

5

4

3

2

1

CCV

CCI

CCS

REF

CLS

LDO

DCIN

MAX1908

MAX8724

THIN QFN

TOP VIEW

Pin Configuration

Ordering Information

MAX1908

MAX8724

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 2; 7/04

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

MAX1908ETI

-40°C to +85°C

28 Thin QFN

MAX8724ETI

-40°C to +85°C

28 Thin QFN