s Complete Standalone Pulse Charger for 1-Cell
s Requires No Microcontroller
s Internal 0.35Ω NMOS Switch
s Sense Resistor Limits Maximum Current for Safety
s Programmable Charge Termination Timer for
Maximum Capacity Charging
s No Blocking Diode Required
s 1% Float Voltage Accuracy
s Near End-of-Charge (C/10) Detection Output
s Low Battery Drain when Input Supply Is Removed
s Automatic Trickle Charge for Low Battery
s Automatic Battery Refresh
s Thermal Shutdown Protection
s Small 8-Pin Thermally Enhanced MSOP Package
s Standalone Lithium-Ion Battery Charger
s Personal Information Appliances
s Cellular Telephones
s Cradle Chargers
Final Electrical Specifications
Pulse Charger with
The LTC®4052 is a complete standalone pulse charger
with integrated MOSFET for 1-cell lithium-ion batteries.
An external sense resistor provides maximum charge
current limiting as a safety precaution against a user
connecting a wall adapter with the incorrect or no current
limit. The internal MOSFET prevents reverse battery
current from flowing if the input voltage is shorted to
ground, eliminating the need for a blocking diode.
As the battery accepts charge and approaches the
programmed float voltage, the internal MOSFET begins
switching off and on with the duty cycle gradually decreas-
ing as the battery approaches a fully charged condition.
A programmable timer ends the charge cycle. The near
end-of-charge C/10 condition is indicated at the CHRG pin
when the average charge current falls to one-tenth of the
wallpack current. Removing the input voltage puts the
LTC4052 into a sleep mode, dropping the battery current
drain to less than 1µA (maximum).
The LTC4052 is available in a tiny 8-pin thermally
enhanced MSOP package.
, LTC and LT are registered trademarks of Linear Technology Corporation.
Single Cell 4.2V, 1A, Standalone Li-Ion Battery Charger
VIN = 4.5V TO 10V
LTC4052 Charge Profile
0 0.5 1.0 1.5 2.0 2.5 3.0
4052 • TA01b
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-
tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.