Features

• Complete Linear Battery Charger with Integrated Buck Converter

• 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
• C/10 Charge Current Detection Output
• 5µA Supply Current in Shutdown Mode

• High Efficiency Synchronous Buck Converter
• 300mA Output Current
• 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

Typical Application

Description

The LTC4080 is a complete constant-current / constant-voltage linear battery charger for a single-cell 4.2V lithium-ion battery with an integrated 300mA synchronous buck converter. The small packages and low external component count make the LTC4080 especially suitable for portable applications. Furthermore, LTC4080 is specifi cally designed to work within USB power specifications.

The CHRG pin indicates when charge current has dropped to ten percent of its programmed value (C/10). An internal 4.5 hour timer terminates the charge cycle. The full-featured LTC4080 battery charger also includes trickle charge, automatic recharge and soft-start (to limit inrush current).

The LTC4080 integrates a synchronous buck converter that is powered from the BAT pin. It has an adjustable output voltage and can deliver up to 300mA of load current. The buck converter also features low-current high-efficiency Burst Mode operation that can be selected by the MODE pin.

The LTC4080 is available in 10-lead, low profile (0.75 mm) 3mm × 3mm DFN and MSOP Exposed Pad packages.