Diodes APM8601 - Manual (Page 2)

APM8601
DUAL CHANNEL SINGLE CELL LINEAR LITHIUM BATTERY
CHARGER WITH 28V OVP and PROGRAMMABLE CHARGE
TIMER
APM8601
Document number: DS35138 Rev. 1 - 2
2 of 14
www.diodes.com
December 2010
© Diodes Incorporated
NEW PROD
UC
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Pin Descriptions
Name Pin # Description
BAT 1, 7
Connection to the
Battery
The battery is charged via this pin and the BAT voltage is constantly monitored.
Connect a bypass capacitor between BAT and GND (2.2µF).
SETI 2
Charge Current
programming
The maximum charge current is programmed using a resistor from SETI to GND.
This also determines the prequal current charging level and top-off threshold.
THM 3 Thermistor Input
To monitor the battery temperature, connect a 10k Ω NTC thermistor. Place this
thermistor as close as possible to the battery. Connect THM to GND if
temperature measurement is not required.
GND 4 Ground Ground connection.
CT 5 Charge Timing
Connecting a capacitor from CT to GND will set the time-outs for prequal, top-off
and fast-charge. Connecting CT direct to GND disables these timers.
USEL 6
USB Charge
Select
Logic input to program the charge current in USB charging mode.
I
BAT
= 90mA when USEL = low, and I
BAT
= 475mA when USEL = high.
EN 8
Enable
(active-low)
The charger is enabled when this input is low. To start the charger connect EN
to GND. Drive this input high to disable the charger.
USB 9 USB Input USB supply input. Connect a bypass capacitor (1µF) from USB to GND.
POK 10
Power OK
(active-low)
When a valid input source is connected, this open-drain output is pulled low.
CHG 11
Charge Status
(active-low)
Open-drain output that indicates the charging status. It is active only in the fast-
charge state and goes high-impedance when the charger is either disabled or in
prequal or top-off mode.
DC 12, 13 DC Input
DC supply input. The recommended input voltage is between 4.32V and 7V. This
input is capable of withstanding up to 28V. Connect both DC pins together on the
PCB. It is recommended to connect a bypass capacitor (1µF) from DC to GND.
FLT 14
Fault Flag
(active-low)
If the prequal or fast-charge timers expire and the charging threshold voltage is
not reached,
FLT (open-drain output) will go low. Remove the fault by cycling
power or raise EN .
EP Exposed Pad
For optimal thermal performance connect to copper on PCB (electrically this can
be GND).