LTC4065-4.4 Linear Technology, LTC4065-4.4 Datasheet - Page 6

• Manufacturer Part Number: LTC4065-4.4
• Description: Standalone 750mA Li-Ion Battery Charge
• Manufacturer: Linear Technology

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PI FU CTIO S
LTC4065-4.4
GND (Pin 1): Ground.
CHRG (Pin 2): Open-Drain Charge Status Output. The
charge status indicator pin has three states: pull-down,
pulse at 2Hz and high impedance state. This output can be
used as a logic interface or as an LED driver. When the
battery is being charged, the CHRG pin is pulled low by an
internal N-channel MOSFET. The pin becomes high im-
pedance when any of the following conditions occur: the
charge current drops below 10% of full-scale current, the
timer ends, or the charger is shut down. If the battery
voltage remains below 2.9V for one quarter of the charge
time, the battery is considered defective and the CHRG pin
pulses at a frequency of 2Hz.
BAT (Pin 3): Charge Current Output. Provides charge
current to the battery and regulates the final float
voltage to 4.4V. An internal precision resistor divider
on this pin sets the float voltage and is disconnected in
shutdown mode.
V
provides power to the charger. V
to 5.5V. This pin should be bypassed with at least a 1µF
capacitor. When V
6
CC
U
(Pin 4): Positive Input Supply Voltage. This pin
U
CC
U
is within 30mV of the BAT pin
CC
can range from 3.75V
voltage, the LTC4065-4.4 enters shutdown mode, drop-
ping I
EN (Pin 5): Enable Input Pin. Pulling this pin above the
manual shutdown threshold (V
the LTC4065-4.4 in shutdown mode. In shutdown mode,
the LTC4065-4.4 has less than 20µA supply current and
less than 1µA battery drain current. Enable is the default
state, but the pin should be tied to GND if unused.
PROG (Pin 6): Charge Current Program and Charge Cur-
rent Monitor Pin. Connecting a 1% resistor, R
ground programs the charge current. When charging in
constant-current mode, this pin servos to 1V. In all modes,
the voltage on this pin can be used to measure the charge
current using the following formula:
Floating the PROG pin sets the charge current to zero.
Exposed Pad (Pin 7): Ground. The Exposed Pad must be
soldered to the PCB ground to provide both electrical con-
tact and rated thermal performance.
I
BAT
BAT
=
to about 1µA.
R
V
PROG
PROG
• 1000
MS
is typically 0.82V) puts
PROG
406544f
, to