LTC4081 Datasheet - Linear Technology

DESCRIPTION
The LTC4081 is a complete constant-current/constant-voltage linear battery charger for a single-cell 4.2V lithium-ion/polymer battery with an integrated 300mA synchronous buck converter. A 3mm × 3mm DFN package and low external component count make the LTC4081 especially suitable for portable applications. Furthermore, the LTC4081 is specifi cally designed to work within USB power specifi cations.

FEATURES
Battery Charger:
■ Constant-Current/Constant-Voltage Operation
   with Thermal Feedback to Maximize Charge Rate
   Without Risk of Overheating
■ Internal 4.5 Hour Safety Timer for Termination
■ Charge Current Programmable Up to 500mA with
   5% Accuracy
■ NTC Thermistor Input for Temperature Qualifi ed
   Charging
■ C/10 Charge Current Detection Output
■ 5μA Supply Current in Shutdown Mode

Switching Regulator:
■ High Effi ciency Synchronous Buck Converter
■ 300mA Output Current (Constant-Frequency Mode)
■ 2.7V to 4.5V Input Range (Powered from BAT Pin)
■ 0.8V to VBAT Output Range
■ MODE Pin Selects Fixed (2.25MHz) Constant-Frequency
   PWM Mode or Low ICC (23μA) Burst Mode® Operation
■ 2μA BAT Current in Shutdown Mode
■ 10-lead, low profile (0.75 mm) 3mm × 3mm DFN
   package

APPLICATIONS
■ Wireless Headsets
■ Bluetooth Applications
■ Portable MP3 Players
■ Multifunction Wristwatches