LTC4011 Linear Technology, LTC4011 Datasheet - Page 6

• Manufacturer Part Number: LTC4011
• Description: High Efficiency Standalone Nickel Battery Charger
• Manufacturer: Linear Technology

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PI FU CTIO S
LTC4011
DCIN (Pin 1): DC Power Sense Input. The LTC4011 senses
voltage on this pin to determine when an external DC
power source is present. This input should be isolated
from V
the Applications Information section for complete details.
Operating voltage range is GND to 34V.
FAULT (Pin 2): Active-Low Fault Indicator Output. The
LTC4011 indicates various battery and internal fault con-
ditions by connecting this pin to GND. Refer to the Opera-
tion and Applications Information sections for further
details. This output is capable of driving an LED and should
be left floating if not used. FAULT is an open-drain output
to GND with an operating voltage range of GND to V
CHRG (Pin 3): Active-Low Charge Indicator Output. The
LTC4011 indicates it is providing charge to the battery by
connecting this pin to GND. Refer to the Operation and
Applications Information sections for further details. This
output is capable of driving an LED and should be left
floating if not used. CHRG is an open-drain output to GND
with an operating voltage range of GND to V
CHEM (Pin 4): Battery Chemistry Selection Input. This pin
should be wired to GND to select NiMH fast charge
termination parameters. If a voltage greater than 2.85V is
applied to this pin, or it is left floating, NiCd parameters are
used. Refer to the Applications Information section for
further details. Operating voltage range is GND to 3.3V.
GND (Pin 5): Ground. This pin provides a single-point
ground for internal references and other critical analog
circuits.
V
LTC4011 provides 3.3V on this pin to drive an external
thermistor network connected between V
GND. Additional power should not be drawn from this pin
by the host application.
V
thermistor network may be connected to V
vide temperature-based charge qualification and addi-
tional fast charge termination control. Charging may also
be paused by connecting the V
6
RT
TEMP
4
U
(Pin 6): Thermistor Network Termination Output. The
CC
(Pin 7): Battery Temperature Input. An external
by a blocking diode or PowerPath FET. Refer to
U
U
TEMP
pin to GND. Refer to
RT,
TEMP
CC
V
.
TEMP
to pro-
CC
and
.
the Operation and Applications Information sections for
complete details on external thermistor networks and
charge control. If this pin is not used it should be wired
to V
V
external voltage divider between BAT and V
to this pin to monitor the average single-cell voltage of the
battery pack. The LTC4011 uses this information to pro-
tect against catastrophic battery overvoltage and to con-
trol the charging state. Refer to the Applications Information
section for further details on the external divider network.
Operating voltage range is GND to BAT.
V
mination. The LTC4011 connects this pin to GND provided
the charger is not in shutdown. V
output to GND with an operating voltage range of GND to
BAT.
TIMER (Pin 10): Charge Timer Input. A resistor connected
between TIMER and GND programs charge cycle timing
limits. Refer to the Applications Information section for
complete details. Operating voltage range is GND to 1V.
SENSE (Pin 11): Charge Current Sense Input. An external
resistor between this input and BAT is used to program
charge current. Refer to the Applications Information
section for complete details on programming charge
current. Operating voltage ranges from (BAT – 50mV) to
(BAT + 200mV).
BAT (Pin 12): Battery Pack Connection. The LTC4011 uses
the voltage on this pin to control current sourced from V
to the battery during charging. Allowable operating volt-
age range is GND to V
TOC (Pin 13): Active-Low Top-Off Charge Indicator Out-
put. The LTC4011 indicates the top-off charge state for
NiMH batteries by connecting this pin to GND. Refer to the
Operation and Applications Information sections for fur-
ther details. This output is capable of driving an LED and
should be left floating if not used. TOC is an open-drain
output to GND with an operating voltage range of GND to
V
CELL
CDIV
CC
.
RT
(Pin 9): Average Cell Voltage Resistor Divider Ter-
. Operating voltage range is GND to 3.3V.
(Pin 8): Average Single-Cell Voltage Input. An
CC
.
CDIV
is an open-drain
CDIV
is attached
4011p
CC