LINEAR Technology, represented in Australia by Soanar , has released the LTC4002-8.4, a standalone switch-mode battery charger controller that can charge a two-cell 8.4V Li-Ion battery at a high rate without compromising board space for heat dissipation.
For safety and autonomous charge control, it includes features such as automatic shutdown, battery preconditioning, battery temperature sensing, an end of charge indicator and a three-hour charge termination timer. It is offered in is offered in 3mm x 3mm DFN and eight-lead SO packages. The complete solution size is 2cm x 2cm. Applications include handheld medical devices, industrial and communication test equipment as well as charging docks, tablet PCs and battery backup systems.
It is a current-mode PWM controller with 500kHz switching frequency. It drives an external P-channel MOSFET for delivering charge currents as high as 4A with an efficiency of up to 90%. The output voltage is set for the final float voltage of 8.4V with ±1% accuracy and charge accuracy of ±5%. The device operates from wall adapters ranging from 9V to 22V.
Its operating frequency and current mode architecture allow the use of small inductors and capacitors. The IC's constant switching frequency minimises noise and filtering needs. The battery charger is stable with all types of output capacitors including low-ESR ceramic capacitors. An internal comparator detects the end-of-charge current and integrated timer sets the total charge time and terminates the charge cycle after three hours. The LTC4002-8.4 automatically enters sleep mode, dropping the battery drain current to 10μA.