Features

• Seamless Transition Between Power Sources: Li-Ion Battery, USB, and 6V to 36V External Supply
• High Efficiency 1.2A Charger from 6V to 36V Input with Adaptive Output Control (LTC4089)
• Load Dependent Charging from USB Input Guarantees Current Compliance
• 215mΩ Internal Ideal Diode plus Optional External Ideal Diode Controller Provides Low Loss Power Path When External Supply/USB Not Present
• Constant-Current/Constant-Voltage Operation with Thermal Feedback to Maximize Charging Rate without Risk of Overheating
• Selectable 100% or 20% Current Limit (e.g., 500mA/100mA) from USB Input
• Preset 4.2V Charge Voltage with 0.8% Accuracy
• C/10 Charge Current Detection Output
• NTC Thermistor Input for Temperature Qualified Charging
• Tiny (6mm × 3mm × 0.75mm) 22-Pin DFN Package

Typical Application

Description

The LTC4089/LTC4089-5 are USB power managers plus high voltage Li-Ion battery chargers. These devices control the total current used by the USB peripheral for operation and battery charging. Battery charge current is automatically reduced such that the sum of the load current and the charge current does not exceed the programmed input current limit. The LTC4089/LTC4089-5 also accommodate high voltage power supplies, such as 12V AC-DC wall adapters, FireWire, or automotive power.

The LTC4089 provides an adaptive output that tracks the battery voltage for high effi ciency charging from the high voltage input. The LTC4089-5 provides a fixed 5V output from the high voltage input to charge single cell Li-Ion batteries. The charge current is programmable and an end-of-charge status output (CHRG) indicates full charge. Also featured is programmable total charge time, an NTC thermistor input used to monitor battery temperature while charging and automatic recharging of the battery.