LTC1734

· 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

Supply Voltage (V_CC) ..................................0.3V to 9V
Input Voltage (BAT, PROG) ........ 0.3V to (V_CC + 0.3V)
Output Voltage (DRIVE) ............. 0.3V to (V_CC + 0.3V)
Output Current (ISENSE) ................................. 900mA
Short-Circuit Duration (DRIVE) ....................... Indefinite
Junction Temperature ........................................ 125°C
Operating Ambient Temperature Range
(Note 2) ...............................................40°C to 85°C
Operating Junction Temperature (Note 2) .......... 100°C
Storage Temperature Range .............65°C to 150°C
Lead Temperature (Soldering, 10 sec)................ 300°C

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  rogramresistor 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 nickelcadmium (NiCd) and nickel-metal-hydride (NiMH) batteries using external termination.