Power management device combines power manager, controller, battery charger

Milpitas, Calif. — Linear Technology Corp. has introduced the highly integrated LTC4098, an autonomous high-efficiency power manager, ideal 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 manages power flow between a wall adapter or USB port, and the device's Li-ion/polymer battery while preferentially providing power to the system load. The LTC4098's single-cell Li-ion/polymer battery charger allows the load current to exceed the current drawn from the USB port while conforming to USB load specifications. For fast charging, the IC's switching input stage converts nearly all of the 2.5 W available from the USB port to system current, enabling up to 700 mA from a 500 mA limited USB port.

For automotive, Firewire, or other high-voltage applications, the LTC4098 provides Bat-Track control of a Linear Technology companion switching regulator up to 38-V operating input (60-V transient). This is said to maximize battery charger efficiency, minimize heat dissipation, and provide for a seamless transition between USB and higher voltage power sources.

The LTC4098 provides an over-voltage protection (OVP) circuit up to 66 V on the USB input — requiring only an external NFET/resistor combination —, which prevents 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 VOUT 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 30 milliohm or less.

There is also an 1.5-A charge current available when wall powered. The charger includes thermal limiting, automatic recharge, stand-alone operation with automatic charge termination and fixed duration safety timer, low-voltage trickle charging, bad battery cell detection and a thermistor input for temperature-qualified charging. The device also features a suspend LDO that prevents battery drain when a device is connected to a suspended USB port.

The LTC4098 is housed in an ultra-thin (0.55 mm) 20-pin 3 x 4-mm QFN package and is guaranteed for operation over a temperature range of -40°C to 85°C.

Pricing: Starts at $2.50 each in quantities of 1,000.
Product information: LTC4098

Linear Technology Corp. , 1-408-432-1900,

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