Linear Technology Develops High Efficiency USB Power Manager and Li-ion Battery Charger

(Product News, 24 Jan 2008)

Linear Technology Corp. has introduced the LTC4098, an autonomous power manager, diode controller and battery charger for portable USB powered devices such as media players, digital cameras, PDAs, personal navigators and smart phones. The LTC4098's switching topology features PowerPath control, which seamlessly manages power flow between a wall adapter or USB port and the device's Li-ion/Polymer battery while providing power to the system load. For automotive, Firewire, or other high-voltage applications, the LTC4098 provides Bat-Track control of a Linear Technology companion switching regulator up to 38V operating input (60V transient), maximizing battery charger efficiency, minimizing heat dissipation, and providing for a seamless transition between USB and higher voltage power sources.

The LTC4098 provides an over-voltage protection (OVP) circuit up to 66V on the USB input—requiring only an external NFET/resistor combination—preventing damage caused by accidental application of high voltage. The LTC4098's "instant-ON" operation ensures system load power at plug-in even with a dead battery. Its onboard ideal diode guarantees that ample power is always available to V_OUT even if there is insufficient power at the LTC4098's two input pins. The IC's ideal diode controller can be used to drive the gate of an optional PFET, reducing the impedance to the battery to 30m¦¸ or less. The LTC4098 is housed in an ultra-thin 20-pin 3x4mm QFN package and is guaranteed for operation from -40°C to 85°C.

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