USB Power Manager and Battery Charger in 18mm2 Package
Linear Technology has introduced the LTC4089 and LTC4089-5, each featuring an autonomous power manager, ideal diode controller and standalone high-voltage switching battery charger for portable USB devices. For high efficiency charging, their switching topology accommodates various inputs, including high voltage power sources up to 36V (40V max) such as 12V AC-DC wall adapters, FireWire ports or automotive batteries. In addition, they accept low-voltage power sources such as 5V wall adapters or USB inputs and single-cell Li-Ion/Li-Polymer batteries.The
The LTC4089's switching regulator features Bat-Track adaptive output control which greatly improves the efficiency of its 1.2A-capable battery charger as the switching regulator's output voltage automatically tracks the battery voltage. The LTC4089-5 provides a fixed 5V output from the high-voltage input to charge single-cell Li-Ion/Li-Polymer batteries. The battery charger's float voltage is preset at 4.2V with guaranteed 1.0% accuracy from 0C to 85C. Charge current is easily programmed using a single resistor. For battery pre-conditioning and qualification, fully discharged cells are automatically trickle charged at 10% of the programmed current until the cell voltage exceeds 2.9V. Total charge time for charge termination is programmed by an external capacitor, and a C/10 charge current detection output is provided. Additional functions include thermal regulation, an NTC thermistor input for temperature-qualified charging, automatic recharging of the battery, reverse current blocking, and under-voltage lockout.
The LTC4089/-5 is housed in a low-profile (0.75mm) tiny 22-pin 6mm x 3mm DFN package, and is guaranteed for operation from -40°C to 85°C. 1,000-piece pricing starts at $2.95 each.