LTC4054LES5-4.2#TRM Linear Technology, LTC4054LES5-4.2#TRM Datasheet - Page 9

• Manufacturer Part Number: LTC4054LES5-4.2#TRM
• Description: IC CHARGR BATTERY L-ION TSOT23-5
• Manufacturer: Linear Technology

Specifications of LTC4054LES5-4.2#TRM

• Function: Charge Management
• Battery Type: Lithium-Ion (Li-Ion)
• Voltage - Supply: 4.25 V ~ 6.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: SOT-23-5 Thin, TSOT-23-5
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: LTC4054LES5-4.2; LTC4054LES5-4.2

OPERATIO
Charge Status Indicator (CHRG)
The charge status output has three different states: strong
pull-down (~10mA), weak pull-down (~20uA), and high
impedance. The strong pull-down state indicates that the
LTC4054L is in a charge cycle. Once the charge cycle has
terminated, the pin state is determined by undervoltage
lockout conditions. A weak pull-down indicates that V
meets the UVLO conditions and the LTC4054L is ready to
charge. High impedance indicates that LTC4054L is in
undervoltage lock-out mode: either V
of the BAT pin voltage or insufficient voltage is applied to
the V
between these three states—this method is discussed in
the Applications Information section.
Thermal Limiting
An internal thermal feedback loop reduces the programmed
charge current if the die temperature attempts to rise
above a preset value of approximately 120 C. This feature
protects the LTC4054L from excessive temperature and
CC
pin. A microprocessor can be used to distinguish
U
POWER ON
UVLO CONDITION
RECONNECTED
Figure 1. State Diagram of a Typical Charge Cycle
I
CHRG: Hi-Z IN UVLO
CC
WEAK PULL-DOWN
SHUTDOWN MODE
CC
STOPS
PROG
DROPS TO <25 A
OTHERWISE
is within 100mV
OR
UVLO CONDITION
PROG FLOATED
OR
CC
allows the user to push the limits of the power handling
capability of a given circuit board without risk of damaging
the LTC4054L. The charge current can be set according to
typical (not worst-case) ambient temperature with the
assurance that the charger will automatically reduce the
current in worst-case conditions. ThinSOT power consid-
erations are discussed further in the Applications Informa-
tion section.
Undervoltage Lockout (UVLO)
An internal undervoltage lockout circuit monitors the input
voltage and keeps the charger in shutdown mode until V
rises above the undervoltage lockout threshold. The UVLO
circuit has a built-in hysteresis of 200mV. Furthermore, to
protect against reverse current in the power MOSFET, the
UVLO circuit keeps the charger in shutdown mode if V
falls to within 30mV of the battery voltage. If the UVLO
comparator is tripped, the charger will not come out of
shutdown mode until V
voltage.
1/10TH FULL CURRENT
NO CHARGE CURRENT
TRICKLE CHARGE
STANDBY MODE
CHRG: STRONG
FULL CURRENT
CHRG: STRONG
CHRG: WEAK
CHARGE MODE
MODE
PULL-DOWN
PULL-DOWN
PULL-DOWN
BAT < 2.9V
BAT > 2.9V
PROG < 100mV
2.9V < BAT < 4.05V
BAT > 2.9V
4054L42 F01
CC
rises 100mV above the battery
LTC4054L-4.2
4054l42f
9
CC
CC