LTC4064 Datasheet, PDF (1/16 Pages) Linear Technology – Monolithic Linear Charger for Back-Up Li-Ion Batteries

LTC4064
Monolithic Linear Charger
for Back-Up Li-Ion Batteries
FEATURES
s _{Preset 4V Charge Voltage with 1% Accuracy}
Prolongs 4.2V Li-Ion Battery Lifetime
s _{Automatic Recharge}
s _{Thermal Regulation Maximizes Charging Rate}
without Risk of Overheating*
s _{No MOSFET, Sense Resistor or Blocking Diode}
Required
s _{Programmable Charge Termination Timer}
s _{Thermistor Input for Temperature Qualified Charging}
s _{Programmable Charge Current with 7% Accuracy}
s _{C/10 Charge Current Detection Output}
s _{25µA Supply Current in Shutdown Mode}
s _{Charge Current Monitor Useful for Gas Gauging*}
s _{Charges Directly from USB Port}
s _{Tiny Thermally Enhanced 10-pin MSOP Package}
U
APPLICATIO S
s _{File Servers, RAID Systems}
s _{Storage Products}
s _{Li-Ion Battery Back-Up}
DESCRIPTIO
The LTC4064 is a standalone linear charger optimized for
prolonging the life of 1-cell Li-ion batteries in battery back-
up applications. By charging to a float voltage of 4V
instead of 4.2V or 4.1V, the LTC4064 decelerates the aging
process and capacity degradation when the battery is
unused for long periods of time but must be in a ready
state.
An external capacitor programs a safety timer to terminate
the charge cycle while the charge current is set externally
with a single resistor. When the input supply is removed,
the LTC4064 automatically enters a low current sleep
mode, dropping the battery drain current to less than 3µA.
Additional safety features designed to maximize battery
lifetime and reliability include NTC temperature sensing
and low battery charge conditioning (trickle charging).
The IC contains an on-chip power MOSFET and eliminates
the need for an external sense resistor and blocking diode.
The LTC4064 also includes C/10 detection circuitry, AC
present logic, and fault detection circuitry.
, LTC and LT are registered trademarks of Linear Technology Corporation.
*US Patent No. 6522118
TYPICAL APPLICATIO
Standalone Back-Up Li-Ion Battery Charger
V_IN = 5V
8
2
SHDN V_CC
4.7µF
BAT ⁹
LTC4064
4 _{TIMER PROG} 7
GND NTC
0.1µF 5, 11 6
I_BAT = 1A
V_FLOAT = 4V
1-CELL
Li-Ion
1.5k BATTERY*
1%
4064TA01
*AN OUTPUT CAPACITOR MAY BE REQUIRED
DEPENDING ON BATTERY LEAD LENGTH
4064f
1