The LTC4001, developed by Linear Technology, is a 2-A-capable, high-efficiency switch-mode battery charger for single-cell, 4.2-V Li-Ion/Li-Polymer batteries that minimizes heat dissipation without compromising board space. Standalone operation eliminates the need for an external microprocessor for charge termination. For safety and autonomous charge control, the LTC4001 includes features such as automatic shutdown, battery pre-conditioning, a thermistor input for temperature-qualified charging, remote sensing, end-of-charge indication and a programmable charge termination timer. The device is intended for 5-V wall adapter input power and can be used with current-limited wall adapters for further reduction in power dissipation.
The LTC4001's synchronously rectified, buck switching topology enables efficiencies as high as 90% at 1.5 A. Final float voltage accuracy is specified at ±1% with charge current accuracy of ±10%. The 1.5-MHz operating frequency and current-mode architecture allow the use of small inductors and capacitors, minimizing noise and filtering needs. The part automatically enters sleep mode, dropping the battery drain current to 5 μA and increasing battery run time.
The LTC4001 is housed in a 16-lead, low-profile (0.75-mm), 4- by 4-mm QFN package. Pricing starts at $2.20 each in 1000-piece quantities. For more information, visit www.linear.com.