Features

• Seamless Transition Between Power Sources: Li-Ion Battery, USB, and 6V to 38V Supply (60V Max)
• 2A Output High Voltage Buck Regulator with Bat-Track™ Adaptive Output Control  (LTC4090)
  
• Internal 215mΩ Ideal Diode Plus Optional External Ideal Diode Controller Provides Low Loss Power Path When External Supply / USB Not Present
• Load Dependent Charging from USB Input Guarantees Current Compliance
• Full Featured Li-Ion Battery Charger
• 1.5A Maximum Charge Current with Thermal Limiting
• NTC Thermistor Input for Temperature Qualified Charging
• Tiny (3mm × 6mm × 0.75mm) 22-Pin DFN Package

Typical Application

Description

The LTC4090/LTC4090-5 are USB power managers plus high voltage Li-Ion/Polymer battery chargers. The 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 LTC4090/LTC4090-5 also accommodate high voltage power supplies, such as 12V AC/DC wall adapters, FireWire, or automotive power.

The LTC4090 provides a Bat-Track adaptive output that tracks the battery voltage for high efficiency charging from the high voltage input. The LTC4090-5 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 are programmable total charge time, an NTC thermistor input used to monitor battery temperature while charging and automatic recharging of the battery.