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LTC4085 Dataheets PDF



Part Number LTC4085
Manufacturers Linear Technology
Logo Linear Technology
Description USB Power Manager
Datasheet LTC4085 DatasheetLTC4085 Datasheet (PDF)

LTC4085 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 PowerPath™ When Wall Adapter/USB Input Not Present n Load Dependent Charging Guarantees Accurate USB Input Current Compliance n Constant-Current/Constant-Voltage Operation with Thermal Feedback to Maximize Charging Rate .

  LTC4085   LTC4085



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LTC4085 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 PowerPath™ When Wall Adapter/USB Input Not Present n Load Dependent Charging Guarantees Accurate USB Input Current Compliance 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., 500mA/100mA) 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 100mA or 500mA). 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 complete 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 100mV 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 is available in a 14-lead low profile 4mm × 3mm DFN package. L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. PowerPath is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents, including 6522118,6700364. Other patents pending. TYPICAL APPLICATION 5V WALL ADAPTER INPUT 5V (NOM) FROM USB CABLE VBUS IIN 4.7μF SUSPEND USB POWER 100mA 500mA SELECT 10k IN SUSP WALL ACPR HPWR PROG LTC4085 OUT GATE CLPROG NTC BAT CHRG VNTC GND TIMER 100k 2k 10k Input and Battery Current vs Load Current ILOAD TO LDOs, REGs, ETC 4.7μF RPROG = 100k, RCLPROG = 2k 600 IIN 500 1k 510Ω 400 ILOAD 300 * 200 IBAT (CHARGING) CURRENT (mA) 100 IBAT + 0.1μF * OPTIONAL - TO LOWER IDEAL DIODE IMPEDANCE 4085 TA01 0 IBAT WALL = 0V (DISCHARGING) –100 0 100 200 300 400 500 600 ILOAD (mA) 4085 TA01b 4085fd 1 LTC4085 ABSOLUTE MAXIMUM RATINGS (Notes 1, 2, 3, 4, 5) Terminal Voltag.


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