The LTC4098-3.6 autonomous high-efficiency power manager, ideal diode controller, and battery charger for one-cell lithium-iron-phosphate (LiFePO4) batteries from Linear Technology targets portable devices such as industrial meters, media players, digital cameras, PDAs, personal navigators, and especially high-peak-power and safety-critical equipment. Its switching topology’s PowerPath control is designed to seamlessly manage power distribution from multiple sources, including 5-V wall adapters, USB, and a LiFePO4 battery while preferentially providing power to the system load. 

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For automotive and other high-voltage applications, the device can interface with a Linear Technology external switching regulator to provide a high-efficiency, high-voltage power path. Its onboard switching regulator can automatically limit its input current for USB compatibility. The low-voltage input and the high-voltage interface both feature Bat-Track optimized charging to provide maximum power to the application and reduced heat in high-power-density applications with input supplies from 5 V to as high as 38 V (60-V absolute maximum).

The LTC4098-3.6 autonomous high-efficiency power manager, ideal diode controller, and battery charger for one-cell LiFePO4 batteries from Linear Technology targets portable devices such as media players, digital cameras, PDAs, personal navigators, and especially high-peak-power and safety-critical equipment.

The LTC4098-3.6 provides an overvoltage protection circuit up to 66 V on the low-voltage input, requiring only an external NFET/resistor combination and thereby preventing damage caused by the accidental application of high voltage. The device’s “instant on” operation ensures system load power at plug-in, even with a fully discharged battery. Its onboard ideal diode guarantees that ample power is always available to VOUT, even if there is insufficient power at the input. Also, the LTC4098-3.6’s idea diode controller can be used to drive the gate of an optional PFET, reducing impedance to the battery to 30 mΩ or less.

The device’s full-featured single-cell LiFePO4 battery charger has a preset 3.6-V charge voltage with 0.5% accuracy. Its 1.5-A charge current is available when the device is wall-powered. When it’s connected to a USB power supply, though, the device 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 the entire 2.5 W available from USB to the system current, enabling up to 700 mA from a 500-mA limited USB port.

Furthermore, the charger includes thermal limiting, automatic recharge, standalone operation with automatic charge termination and fixed one-hour safety timer, bad-battery-cell detection, and a thermistor input for 0°C to 60°C temperature-qualified charging. A suspend low-dropout regulator (LDO) helps to prevent battery drain when a device is connected to a suspended USB port. The LTC4098-3.6 comes in a low-profile (0.755 mm), 20-pin, 3- by 4-mm quad flat no-lead (QFN) package with guaranteed operation from –40°C to 85°C. Pricing in quantities of 1000 units starts at $2.65 each.