DC Input Sources

The MAX8808X/MAX8808Y/MAX8808Z operate from

well-regulated DC sources. The full charging input volt-

age range is 4.25V to 7V. The device can withstand up

greater than 7V, the internal overvoltage-protection cir-

cuitry disables charging until the input falls below 7V.

An appropriate power supply must provide at least

4.25V at the desired peak charging current. It also must

stay below 6.5V when unloaded.

Application Circuits

Stand-Alone Li+ Charger

The MAX8808X/MAX8808Y/MAX8808Z provide a com-

alone Li+ battery charger. The 2.8k

Ω resistor

connected to ISET sets a charging current of 465mA.

The LED connected to the CHG output indicates when

either fast-charge or precharge qualification has

begun. When the battery is full, CHG turns high imped-

ance and the LED turns off.

Microprocessor-Interfaced Charger

battery charger. The MAX8808X begins charging the bat-

tery when EN is low. The µP can drive EN high to disable

the charger. The MAX8808X generates a ACOK signal to

indicate the presence of an input supply. CHG is used to

detect the charge status of the battery. By monitoring

1A Linear Li+ Battery Chargers with Integrated Pass

FET and Thermal Regulation in 2mm x 2mm TDFN

_______________________________________________________________________________________

9

MAX8808X

(MAX8808Y)

MAX8808Z

IN

4.2V

Li+

R3

100k

Ω

AC-INPUT

PRESENT

INDICATOR

R2

510

Ω

C2

1

µF

C3

0.47

µF

C1

1

µF

4.25V TO 15V

ISET

VL

GND

EN (EN)

CHG

R1

2.8k

Ω

ENABLE

INPUT

BATT

ACOK

MAX8808XETA

IN

4.2V

Li+

C2

1

µF

C1

1

µF

AC/DC

ADAPTER

ISET

EN

CHG

SYSTEM

VL

BATT

R1

2.8k

Ω

GND

C3

0.47

µF

R4

100k

Ω

ACOK

R3

100k

Ω

R2

10k

Ω

CHARGE-CURRENT MONITOR

LOW: CHARGE, HIGH: FULL OR OFF

C4

0.1

µF