LTC4058EDD-4.2 Linear Technology, LTC4058EDD-4.2 Datasheet - Page 8

• Manufacturer Part Number: LTC4058EDD-4.2
• Description: IC CHARGER BATTERY LI-ION 8-DFN
• Manufacturer: Linear Technology

Specifications of LTC4058EDD-4.2

• 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: 8-WFDFN Exposed Pad
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

OPERATIO
LTC4058-4.2/LTC4058X-4.2
Power Supply Status Indicator (ACPR)
The power supply status output has two states: pull-down
and high impedance. The pull-down state indicates that
V
above the battery voltage. When these conditions are not
met, the ACPR pin is high impedance indicating that the
LTC4058 is unable to charge the battery.
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 LTC4058 from excessive temperature and allows the
user to push the limits of the power handling capability of
a given circuit board without risk of damaging the LTC4058.
The charge current can be set according to typical (not worst
case) ambient temperature with the assurance that the
8
POWER ON
UVLO CONDITION
EN DRIVEN LOW
CC
is above the UVLO threshold (3.8V) and is also 100mV
I
CC
SHUTDOWN MODE
Figure 1. State Diagram of a Typical Charge Cycle
STOPS
DROPS TO <25 A
CHRG: Hi-Z
OR
UVLO CONDITION
EN DRIVEN HIGH
U
OR
1/10TH FULL CURRENT
NO CHARGE CURRENT
TRICKLE CHARGE
STANDBY MODE
CHRG: STRONG
FULL CURRENT
CHRG: STRONG
CHRG: Hi-Z
CHARGE MODE
405842 F01
MODE
PULL-DOWN
PULL-DOWN
BSENSE < 2.9V
BSENSE > 2.9V
PROG < 100mV
2.9V < BSENSE < 4.1V
BSENSE > 2.9V
charger will automatically reduce the current in worst-case
conditions. DFN power considerations are discussed fur-
ther in the Applications Information 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 BSENSE voltage. If the UVLO
comparator is tripped, the charger will not come out of
shutdown mode until V
voltage.
Manual Shutdown
At any point in the charge cycle, the LTC4058 can be put
into shutdown mode by driving the EN pin high. This
reduces the battery drain current to less than 2 A and the
supply current to less than 50 A. When in shutdown
mode, the CHRG pin is in the high impedance state. A new
charge cycle can be initiated by driving the EN pin low. A
resistor pull-down on this pin forces the LTC4058 to be
enabled if the pin is allowed to float.
Automatic Recharge
Once the charge cycle is terminated, the LTC4058 continu-
ously monitors the voltage on the BSENSE pin using a
comparator with a 2ms filter time (t
cycle restarts when the battery voltage falls below 4.10V
(which corresponds to approximately 80% to 90% battery
capacity). 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 enters
a pull-down state during recharge cycles.
CC
rises 100mV above the BSENSE
RECHARGE
sn405842 405842fs
). A charge
CC
CC