LTC1729CMS8-4.2 Linear Technology, LTC1729CMS8-4.2 Datasheet - Page 5

• Manufacturer Part Number: LTC1729CMS8-4.2
• Description: IC CTRLR BATT CHRGR LI-ION 8MSOP
• Manufacturer: Linear Technology

Specifications of LTC1729CMS8-4.2

• Function: Charge Management
• Battery Type: Lithium-Ion (Li-Ion)
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

PI FU CTIO S
OVP (Pin 1): Connection to an Internal Precision Resistor
Divider Used as a Voltage Feedback Monitor for Constant-
Voltage Mode Charging.
BAT (Pin 2): Input to Battery Monitor Circuits and OVP
Resistor Divider. The battery monitor circuits activate
trickle charge preconditioning, battery present detection
and C/10 current detection. This pin is in a high impedance
state when V
old. During trickle charge preconditioning and charging
the BAT pin sources 12mA and 1.3mA respectively. The
current sources are clamped from driving the BAT pin
above 4.5V/cell with an internal pull-down transistor.
In the No Bat, Done and Pause states or the Hold and Reset
modes, the current sources are turned off, leaving only the
55k OVP divider as a load on the BAT pin. Most chargers
have a 200 A current source that will compensate for this
50 A to 80 A load.
SENSE (Pin 3): Input to C/10 Current Detection Circuit.
This pin sinks 100 A during the Charge state which is used
to program the C/10 current threshold.
GND (Pin 4): Ground.
NTC (Pin 5): Input to the NTC Thermistor Monitoring
Circuits. When the voltage on this pin is above 2.79V
(cold) or below 0.405V (hot), the state machine is locked
in the present state and the timer is stopped. This is called
the Hold mode. While in the Hold mode, the charger is
turned off via the V
and SENSE pins are turned off. The STATUS pin is not
affected.
U
U
CC
is below the undervoltage lockout thresh-
C
U
pin and the current sources on BAT
If the NTC pin is below 0.2V, the state machine is forced
in the reset mode with all the timers cleared to zero. The
current sources on the BAT pin and SENSE pin are
disabled leaving the 55k OVP divider. The STATUS pin is
pulled low in the Reset mode.
There is a 100 A current source on the NTC pin to bias the
NTC thermistor. This current source is active when the V
is greater than the undervoltage lockout threshold.
STATUS (Pin 6): Open-Drain Output for C/10 Charge
Termination Detection Circuit. When in the Charge state,
this pin is pulled low. Once the charge current drops below
the C/10 current threshold for three seconds, the pull-
down transistor is disabled, and a 50 A pull-down current
sink remains activated until the 1- or 3-hour time-out or
the battery or wall adapter is removed.
V
When this pin is open circuit, the charger is active.
Normally this pin allows the charger to be active for three
hours.
V
operation, V
turning off when V
tions, the undervoltage lockout is 10.4V with a minimum
V
undervoltage lockout and put the IC in a high impedance
condition. When the supply is connected, the IC is initial-
ized in the Reset mode with the state machine forced in the
Charge state with all the timers set to zero.
C
CC
CC
(Pin 7): Open-Drain Output for Turning Off the Charger.
(Pin 8): Input Supply. For 4.1V or 4.2V single cell
of 12V. Removing the wall adapter will trigger an
CC
should be between 8V and 28V with the IC
CC
drops below 6V. For 2-cell applica-
LTC1729 Series
5
CC