General Description

The MAX1908/MAX8724/MAX8765/MAX8765A highly

integrated, multichemistry battery-charger control ICs

simplify the construction of accurate and efficient charg-

ers. These devices use analog inputs to control charge

current and voltage, and can be programmed by the host

or hardwired. The MAX1908/MAX8724/MAX8765/

MAX8765A achieve high efficiency using a buck topology

with synchronous rectification.

The MAX1908/MAX8724/MAX8765/MAX8765A 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/MAX8765A provide out-

puts to monitor current drawn from the AC adapter (DC

input source), battery-charging current, and the pres-

ence 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/MAX8765A do not.

The MAX1908/MAX8724/MAX8765/MAX8765A 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

Handheld Terminals

Features

o ±0.5% Output Voltage Accuracy Using Internal

Reference (±0.4% for MAX8765A, 2-/3-Cell Only)

o ±4% Accurate Input Current Limiting

o ±5% Accurate Charge Current

o Analog Inputs Control Charge Current and

Charge Voltage

o Outputs for Monitoring

Current Drawn from AC Adapter

Charging Current

AC Adapter Presence

o Up to 17.6V Battery-Voltage Set Point

o Maximum 28V Input Voltage

o > 95% Efficiency

o Shutdown Control Input

o 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

MAX8765A

THIN QFN

TOP VIEW

Pin Configuration

Ordering Information

MAX1908

MAX8724

MAX8765

MAX8765A

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 5; 11/09

For pricing, delivery, and ordering information, please contact Maxim 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-EP*

MAX8724ETI+

-40°C to +85°C

28 Thin QFN-EP*

MAX8765ETI+

-40°C to +85°C

28 Thin QFN-EP*

MAX8765AETI+

-40°C to +85°C

28 Thin QFN-EP*

+

Denotes a lead(Pb)-free/RoHS-compliant package.

*

EP = Exposed pad.