LTC4065LEDC#TRMPBF Linear Technology, LTC4065LEDC#TRMPBF Datasheet - Page 9

• Manufacturer Part Number: LTC4065LEDC#TRMPBF
• Description: IC CHARGER LI-ION 6-DFN
• Manufacturer: Linear Technology

Specifications of LTC4065LEDC#TRMPBF

• Function: Charge Management
• Battery Type: Lithium-Ion (Li-Ion)
• Voltage - Supply: 3.75 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 6-WFDFN Exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

OPERATIO
Undervoltage Lockout (UVLO)
An internal undervoltage lockout circuit monitors the input
voltage and keeps the charger in undervoltage lockout
until V
the BAT pin voltage. The 3.6V UVLO circuit has a built-in
hysteresis of approximately 0.6V and the automatic shut-
down threshold has a built-in hysteresis of approximately
50mV. During undervoltage lockout conditions, maxi-
mum battery drain current is 4µA and maximum supply
current is 11µA.
Shutdown Mode
The LTC4065L can be disabled by pulling the EN pin above
the shutdown threshold (approximately 0.82V). In shut-
down mode, the battery drain current is reduced to less
than 1µA and the supply current to about 20µA.
Timer and Recharge
The LTC4065L has an internal termination timer that
starts when an input voltage greater than the undervoltage
lockout threshold is applied to V
shutdown the battery voltage is less than the recharge
threshold.
At power-up or when exiting shutdown, if the battery
voltage is less than the recharge threshold, the charge
time is set to 4.5 hours. If the battery voltage is greater than
the recharge threshold at power-up or when exiting shut-
down, the timer will not start and charging is prevented
since the battery is at or near full capacity.
Once the charge cycle terminates, the LTC4065L continu-
ously monitors the BAT pin voltage using a comparator
with a 2ms filter time. When the average battery voltage
CC
rises above 3.6V and approximately 80mV above
U
CC
, or when leaving
falls below 4.1V (which corresponds to 80% to 90%
battery capacity), a new charge cycle is initiated and a 2.25
hour timer begins. This ensures that the battery is kept at,
or near, a fully charged condition and eliminates the need
for periodic charge cycle initiations. The CHRG output
assumes a strong pull-down state during recharge cycles
until C/10 is reached when it transitions to a high
impendance state.
Trickle Charge and Defective Battery Detection
At the beginning of a charge cycle, if the battery voltage is
low (below 2.9V), the charger goes into trickle charge,
reducing the charge current to 10% of the full-scale
current (Note: The LTC4065LX has full charge current at
low-battery voltage). If the low-battery voltage persists for
one quarter of the total time (1.125 hour), the battery is
assumed to be defective, the charge cycle is terminated
and the CHRG pin output pulses at a frequency of 2Hz with
a 75% duty cycle. If for any reason the battery voltage rises
above 2.9V, the charge cycle will be restarted. To restart
the charge cycle (i.e., when the defective battery is re-
placed with a discharged battery), simply remove the input
voltage and reapply it or temporarily pull the EN pin above
the shutdown threshold.
CHRG Status Output Pin
The charge status indicator pin has three states: pull-
down, pulse at 2Hz (see Trickle Charge and Defective
Battery Detection) and high impedance. The pull-down
state indicates that the LTC4065L is in a charge cycle. A
high impedance state indicates that the charge current has
dropped below 10% of the full-scale current or the
LTC4065L is disabled. Figure 2 shows the CHRG status
under various conditions.
LTC4065L/LTC4065LX
4065lxfa
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