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
• 3.95V Float Voltage Improves Battery Lifespan and High Temperature Safety Margin
• Load Dependent Charging from USB Input
• Guarantees Current Compliance 215m 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 3.95V 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-Lead DFN Package

Typical Application

Description

The LTC®4089-3 is a USB power manager plus high voltage Li-Ion battery charger. This device controls 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 LTC4089-3 also accommodates high voltage power supplies, such as 12V AC/DC wall adapters, Firewire, or automotive power.

The LTC4089-3 provides an adaptive output that tracks the battery voltage for high efficiency charging from the high voltage input. This 3.95V version of the the standard LTC4089 is intended for applications which have extended battery lifetime requirements or those that require high temperature (approximately >60°C) operation or storage. Under these conditions, a reduced float voltage will trade-off initial cell capacity for the benefit of increased capacity retention over the life of the battery. The charge current is programmable and an end-of-charge status output (CHRG) indicates full charge. Also featured are programmable total charge time, an NTC thermistor input used to monitor battery temperature while charging and automatic recharging of the battery.