MAX1508 Maxim, MAX1508 Datasheet - Page 6

• Manufacturer Part Number: MAX1508
• Description: Linear Li Battery Charger with Integrated Pass FET / Thermal Regulation / and ACOKin 3mm x 3mm TDFN
• Manufacturer: Maxim

Linear Li+ Battery Charger with Integrated Pass FET,
Thermal Regulation, and ACOK in 3mm x 3mm TDFN
CHG is an open-drain current source for indicating
charge status. Table 1 describes the state of CHG dur-
ing different stages of operation.
CHG is a nominal 12mA current source suitable for dri-
ving a charge-indication LED. If the MAX1508 is used
in conjunction with a microprocessor, a pullup resistor
to the logic I/O voltage allows CHG to indicate charge
status to the µP instead of driving an LED.
Figure 1. Functional Diagram
6
_______________________________________________________________________________________
0.47µF
ISET
CHG
CHG Charge Indicator Output
IN
VL
( ) ARE FOR MAX1508Y ONLY
N
IREF
REF
VL
IN
V
V
REFOK
INOVLO
LUVLO
IN
INOK
OUTPUT DRIVER,
CURRENT SENSE,
AND LOGIC
REFOK
V
LOK
An analog soft-start algorithm activates when entering
fast-charge mode. When the prequalification state is
complete (V
ramps up in 3ms to the full charging current. This
reduces the inrush current on the input supply. Since
the MAX1508Y and MAX1508Z do not have a prequali-
fication state, they automatically enter soft-start upon
activation.
ON
BATT
IN
BATT
100°C
LOGIC
TEMPERATURE
MAX1508
GND
SENSOR
exceeds +2.5V), the charging current
MAX1508Z ONLY
MAX1508 AND
V
REF
200kΩ
N
ACOK
BATT
EN (EN)
Soft-Start
VI/O