DESCRIPTION
The LTC®3554 family* are micropower, highly integrated power management and battery charger ICs for single-cell Li-Ion/Polymer battery applications. They include a PowerPath™ manager with automatic load prioritization, a battery charger, an ideal diode and numerous internal protection features. Designed specifically for USB applications, the LTC3554 power managers automatically limit input current to a maximum of either 100mA or 500mA. Battery charge current is automatically reduced such that the sum of the load current and the charge current does not exceed the selected input current limit.

FEATUREs
■ 10μA Standby Mode Quiescent Current (All Outputs On)
■ Seamless Transition Between Input Power Sources: Li-Ion/Polymer Battery and USB
■ 240mΩ Internal Ideal Diode
■ Dual High Efficiency Step-Down Switching Regulators (200mA IOUT) with Adjustable Output Voltages
■ Pushbutton On/Off Control with System Reset
■ Reset Time: 5 sec (LTC3554/LTC3554-1), 14 sec (LTC3554-2/LTC3554-3)
■ Full Featured Li-Ion/Polymer Battery Charger
■ Programmable Charge Current with Thermal Limiting
■ Instant-On Operation with Discharged Battery
■ Battery Float Voltage: 4.2V (LTC3554/LTC3554-2/LTC3554-3), 4.1V (LTC3554-1)
■ 3mm × 3mm × 0.75mm 20-Lead QFN Package

APPLICATIONS
■ USB-Based Handheld Products
■ Portable Li-Ion/Polymer Based Electronic Devices
■ Fitness Computers
■ Low Power Medical Devices