LTC1731-4.2 Datasheet | Linear Technology

Features s plete Linear Charger Controller for 1-Cell Lithium-Ion Batteries s 1% Voltage Accuracy s Programmable Charge Current s C/10 Charge Current Detection Output s Programmable Charge Termination Timer s Space Saving 8-Pin MSOP Package s Automatic Sleep Mode When Input Supply is Removed (7µA Battery Drain) s Automatic Trickle Charging of Low Voltage Cells s Programmable for Constant-Current-Only Mode U APPLICATIO S s Cellular Phones s Handheld puters s Charging Docks and Cradles s Programmable Current Source LTC1731-4.1/LTC1731-4.2 Single Cell Lithium-Ion Linear Battery Charger Controllers DESCRIPTIO The LTC®1731 is a plete constant-current/constantvoltage linear charger controller for single cell lithium-ion batteries. Nickel-cadmium (Ni Cd) and nickel-metal-hydride (Ni MH) batteries can also be charged with constant current using external termination. The external sense resistor sets the charge current with 5% accuracy. An internal resistor divider and precision reference set the final float potential with ±1% accuracy. The output float voltage is set internally to 4.1V (LTC1731-4.1) or 4.2V (LTC1731-4.2). When the input supply is removed, the LTC1731 automatically enters a low current sleep mode, dropping the battery drain current to typically 7µA. An internal parator 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 cell voltage exceeds 2.457V. The LTC1731 is available in the 8-pin MSOP and SO packages. , LTC and LT are registered trademarks of Linear Technology Corporation. TYPICAL APPLICATIO 500m A Li-Ion Battery Charger VIN = 6V MBRM120T3 CHARGE STATUS CTIMER 0.1µF 1k 2 7 VCC SENSE CHRG DRV 8 6 3 TIMER 1 BAT 5 PROG RPROG- 19.6k RSENSE 0.2Ω Q1 Si9430DY IBAT = 500m A + Li-ION CELL 1µF 10µF - SHUTDOWN INVOKED BY FLOATING THE PROG...