Li-Ion Charger from Linear Delivers up to 2A in 16mm² Package
Linear Technology Corporation has added the LTC4001, a 2A capable, high efficiency switch-mode battery charger for single-cell 4.2V 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 preconditioning, a thermistor input for temperature-qualified charging, remote sensing, end-of-charge indication and a programmable charge termination timer.
The device is intended for 5V wall adapter input power and is suited for applications including handheld medical devices, handheld computers, charging docks and cradles, digital cameras and smart phones. It may also be used with current limited wall adapters for even further reduction in power dissipation.
The LTC4001's synchronously rectified, buck switching topology enables efficiencies as high as 90% @1.5A. Final float voltage accuracy is specified at 1% with charge current accuracy of 10%. The LTC4001's high operating frequency of 1.5MHz and current mode architecture allow the use of small inductors and capacitors, minimizing noise and filtering needs. The LTC4001 automatically enters sleep mode, dropping the battery drain current to 5uA and increasing battery run time.
The LTC4001 is housed in a compact 16-lead, low-profile (0.75mm) 4mm x 4mm QFN package. It is guaranteed for operation from -40°C to 85°C. Pricing starts at $2.20 each in 1,000-piece quantities.
