LTC1731-8.4

· Complete Linear Charger Controller for 2-Cell Lithium-Ion Batteries
· 1% Voltage Accuracy
· Programmable Charge Current
· C/10 Charge Current Detection Output
· Programmable Charge Termination Timer
· Space Saving 8-Pin MSOP Package
· Automatic Sleep Mode When Input Supply is Removed (15mA Battery Drain)
· Automatic Trickle Charging of Low Voltage Cells
· Programmable for Constant-Current-Only Mode

· Cellular Phones
· Handheld Computers
· Charging Docks and Cradles
· Programmable Current Source

Input Supply Voltage (V_CC) ...................................... 13.2V
SENSE, DRV, BAT, TIMER, PROG ................... 0.3V to V_CC
CHRG........................................................ 0.3V to 13.2V
Operating Temperature Range (Note 2) ....40° to 85°C
Storage Temperature Range .................65°C to 150°C
Lead Temperature (Soldering, 10 sec).................... 300°C

The LTC^®1731-8.2/LTC1731-8.4 are complete constantcurrent/ constant-voltage linear charger controllers for 2- cell lithium-ion (Li-Ion)batteries. Nickel-cadmium (NiCd) and nickel-metal-hydride (NiMH) batteries can also be charged with constant current using external termination. The external sense resistor sets the charge current with 7% accuracy. An internal resistor divider and precision reference set the final float potential with 1% accuracy. The output float voltages are set internally to 8.2V (LTC1731-8.2) or 8.4V (LTC1731-8.4).

When the input supply is removed, the LTC1731-8.2/ LTC1731-8.4 automatically enter a low current sleep mode, dropping the battery drain current to typically 15mA. An internal comparator detects the end-of-charge (C/10) condition while a programmable timer, using an external capacitor, sets the total charge time. Fully discharged cells are automatically trickle charged at 10% of the programmed current until battery voltage exceeds 4.95V.

The LTC1731-8.2/LTC1731-8.4 are available in the 8-pin MSOP and SO packages. For 1-cell Li-Ion battery charging, see the LTC1731-4.1 and LTC1731-4.2 data sheets.