Functional Pin Description
VIN (Pin 1, 15, 16)
VIN is the input power source pin that is connected to a wall
FAULT (Pin 2)
FAULT is an open-drain output indicating fault status. When
a fault condition occurs, this pin is pulled to LOW.
STATUS (Pin 3)
STATUS is an open-drain output indicating charging and
inhibit states. During any charge mode, this pin is pulled to
TIME (Pin 4)
Connect a timing capacitor CTIME between this pin and
GND. The internal oscillator, as shown in the Block Diagram,
charges and discharges the timing capacitor between 0.5V
and 1.5V with 10µA current. The oscillation period can be
TOSC = 0.2 ⋅ 106 ⋅ CTIME
A 22-stage binary counter increments each oscillation period
to set up the TIMEOUT interval. The TIMEOUT interval can
be calculated as:
222 ⋅ TOSC=
When the fast charge takes longer than the TIMEOUT
interval, or the Trickle charge time exceeds 1/8 of the
TIMEOUT interval, the charger issues a TIMEOUT fault
status and stops charging.
The oscillator also provides a time reference for the charger.
GND (Pin 5)
GND is the connection to system ground.
TOEN (Pin 6)
TOEN is the TIMEOUT enable input pin. Pulling this pin to
LOW disables the TIMEOUT charge-time limit for the fast
charge modes. Leave this pin floating to enable the
TIMEOUT limit. An internal 10µA pull-up circuit pulls this pin
up to a 2.8V internal reference. The trickle mode always has
the 1/8 TIMEOUT limited charge time regardless of this
input. When a TIMEOUT fault is issued, the charger is
latched. The only way to enable the charger again is to cycle
the input power, or to toggle the EN pin.
EN (Pin 7)
EN is the CMOS logic input. Leave this pin floating to enable
the charger. This pin is pulled up to the internal 2.8V
reference via a 10µA current source.
V2P8 (Pin 8)
V2P8 is a 2.8V reference voltage output. V2P8 pin outputs a
2.8V voltage when the input voltage rises above the POR
threshold and outputs zero voltage otherwise. This pin can
be used as an adapter presence signal. A 0.1µF Ceramic
capacitor is recommended for decoupling purposes. This pin
can be used to bias other circuits with a maximum current of
IREF (Pin 9)
IREF is the programming input for the constant charge
current. Connect a resistor RIREF (see the Typical
Application) to this pin. The voltage of this pin is regulated to
a 0.8V reference voltage. The charging current during the
constant current mode charge is 100,000 times of the
current in the RIREF resistor. The charging current in the
constant current mode can be found as:
where VREF is the 0.8V reference voltage.
IMIN (Pin 10)
IMIN is a programmable input for the end-of-charge current.
The pin voltage is also regulated at 0.8V. The end-of-charge
current can be found as:
TEMP (Pin 11)
TEMP is an Input for an external NTC thermistor. As shown
in the Block Diagram, two comparators forms a window
comparator with its low and high thresholds set by VTMIN
and VTMAX respectively. When the voltage on the TEMP pin
is outside the window, the charger stops. When the TEMP
pin voltage falls back into the window, the charger starts a
new charge cycle. The VTMIN and VTMAX voltage is
determined by the internal resistor divider, as shown in the
block diagram. See “Battery Pack Temperature Monitoring”
for more information.
The TEMP pin is also used for battery removal detection. It
is assumed that the thermistor is co-packed with the battery.
When the charger sees a TEMP pin voltage that is 2.1V or
higher, it assumes that the battery is removed. When a
battery is removed, a FAULT signal is indicated and
charging is halted. When a battery is inserted again, a new
charge cycle starts.
VBAT (Pin 12, 13, 14)
VBAT is the connection to a battery. Typically a 10µF
Tantalum capacitor is needed for stability when no battery is
attached to this pin. When a battery is connected, however,
no capacitor is required for stability. A 0.1µF ceramic
capacitor is recommended for decoupling.