Datasheet

1
LTC1734
Lithium-Ion Linear
Battery Charger in ThinSOT
The LTC
®
1734 is a low cost, single cell, constant-current/
constant-voltage Li-Ion battery charger controller. When
combined with a few external components, the SOT-23
package forms a very small, low cost charger for single cell
lithium-ion batteries.
The LTC1734 is available in 4.1V and 4.2V versions with
1% accuracy. Constant current is programmed using a
single external resistor between the PROG pin and ground.
Manual shutdown is accomplished by floating the pro-
gram resistor while removing input power automatically
puts the LTC1734 into a sleep mode. Both the shutdown
and sleep modes drain near zero current from the battery.
Charge current can be monitored via the voltage on the
PROG pin allowing a microcontroller or ADC to read the
current and determine when to terminate the charge cycle.
The output driver is both current limited and thermally
protected to prevent the LTC1734 from operating outside
of safe limits. No external blocking diode is required.
The LTC1734 can also function as a general purpose
current source or as a current source for charging nickel-
cadmium (NiCd) and nickel-metal-hydride (NiMH) batter-
ies using external termination.
Low Profile (1mm) ThinSOT
TM
Package
No Blocking Diode Required
No Sense Resistor Required
1% Accurate Preset Voltages: 4.1V or 4.2V
Charge Current Monitor Output
for Charge Termination
Programmable Charge Current: 200mA to 700mA
Automatic Sleep Mode with Input Supply Removal
Manual Shutdown
Negligible Battery Drain Current in Shutdown
Undervoltage Lockout
Self Protection for Overcurrent/Overtemperature
Cellular Telephones
Handheld Computers
Digital Cameras
Charging Docks and Cradles
Low Cost and Small Size Chargers
Programmable Current Sources
, LTC and LT are registered trademarks of Linear Technology Corporation.
300mA Li-Ion Battery Charger
PROG Pin Indicates Charge Status
FEATURES
DESCRIPTIO
U
APPLICATIO S
U
TYPICAL APPLICATIO
U
V
IN
5V
I
BAT
= 300mA
1734 TA01
SINGLE
Li-Ion
BATTERY
10µF
+
GND
PROG
DRIVE
BAT
2
4
6
5
LTC1734
V
CC
I
SENSE
31
1µF
R
PROG
5k
FMMT549
CHARGING
BEGINS
CHARGING
COMPLETE
1734 TA01b
5V
4V
3V
2V
1V
0V
1.5V
V
BAT
CONSTANT
CURRENT
V
BAT
(V)V
PROG
(V)
CONSTANT
VOLTAGE
V
PROG
ThinSOT is a trademark of Linear Technology Corporation.

Summary of content (12 pages)