Datasheet

Thermal Regulation
The thermal-regulation loop limits the MAX8808X/
MAX8808Y/MAX8808Z die temperature to +115°C by
reducing the charge current as necessary. This feature
not only protects the ICs from overheating, but also
allows a higher charge current without risking damage
to the system.
EN (MAX8808X/MAX8808Z) and EN
(MAX8808Y) Charger Enable Input
The MAX8808X/MAX8808Z contain an active-low logic
input (EN) used to enable the charger. Drive EN low,
leave floating, or connect to GND to enable the
charge-control circuitry. Drive EN high to disable the
charger-control circuitry. EN has a 200kΩ internal pull-
down resistor.
The MAX8808Y contains an active-high enable input
(EN) to enable the charger. Drive EN high to enable the
charge-control circuitry. Drive EN low to disable the
charger-control circuitry. Do not leave EN floating. It
has no internal pullup or pulldown resistor.
ACOK Output
The open-drain ACOK output asserts low when +4.25V
≤ V
IN
≤ +7V and V
IN
- V
BATT
≥ 40mV. ACOK requires
an external pullup resistor (100kΩ typ). ACOK is high
impedance during shutdown.
MAX8808X/MAX8808Y/MAX8808Z
1A Linear Li+ Battery Chargers with Integrated Pass
FET and Thermal Regulation in 2mm x 2mm TDFN
_______________________________________________________________________________________ 7
ASYNCHRONOUS
FROM ANYWHERE
V
IN
> 7V OR
V
BATT
> V
IN
OR
IC DISABLED
SHUTDOWN
CHARGER = OFF
CHG = HIGH
V
IN
< 7V AND
V
IN
> V
BATT
AND
IC ENABLED
V
IN
< 7V AND
V
IN
> V
BATT
AND
IC ENABLED
FAST-CHARGE
100% CHARGER CURRENT
CHG = LOW
TOP-OFF
CHG = HIGH
TOP-OFF CONTINUES
TO REGULATE BATT AT
4.2V
I
CHARGE
< 10%
OF I
SET
I
CHARGE
> 20%
OF I
SET
PREQUAL
10% CHARGE CURRENT
CHG = LOW
V
BATT
> 2.5V
V
BATT
< 2.5V
V
BATT
< 2.4V
MAX8808X
MAX8808Y/
MAX8808Z
V
IN
> 7V OR
V
BATT
> V
IN
OR
IC DISABLED
Figure 2. Charge-State Diagram