LTC4085 Datasheet | Linear Technology

Features USB Power Manager with Ideal Diode Controller and Li-Ion Charger DESCRIPTION n Seamless Transition Between Input Power Sources: Li-Ion Battery, USB and 5V Wall Adapter n 215mΩ Internal Ideal Diode Plus Optional External Ideal Diode Controller Provide Low Loss Power Path™ When Wall Adapter/USB Input Not Present n Load Dependent Charging Guarantees Accurate USB Input Current pliance n Constant-Current/Constant-Voltage Operation with Thermal Feedback to Maximize Charging Rate Without Risk of Overheating- n Selectable 100% or 20% Input Current Limit (e.g., 500m A/100m A) n Battery Charge Current Independently Programmable Up to 1.2A n Preset 4.2V Charge Voltage with 0.8% Accuracy n C/10 Charge Current Detection Output n NTC Thermistor Input for Temperature Qualified Charging n Tiny (4mm × 3mm × 0.75mm) 14-Lead DFN Package APPLICATIONS n Portable USB Devices: Cameras, MP3 Players, PDAs The LTC®4085 is a USB power manager and Li-Ion battery charger designed for portable battery-powered applications. The part controls the total current used by the USB peripheral for operation and battery charging. The total input current can be limited to 20% or 100% of a programmed value up to 1.5A (typically 100m A or 500m A). Battery charge current is automatically reduced such that the sum of the load current and charge current does not exceed the programmed input current limit. The LTC4085 includes a plete constant-current/ constant-voltage linear charger for single cell Li-ion batteries. The float voltage applied to the battery is held to a tight 0.8% tolerance, and charge current is programmable using an external resistor to ground. An end-of-charge status output CHRG indicates full charge. Total charge time is programmable by an external capacitor to ground. When the battery drops 100m V below the float voltage, automatic recharging of the battery occurs. Also featured is an NTC thermistor input used to monitor battery temperature while charging. The LTC4085...