AnalogicTech's new charger IC improves battery performance in today's portable electronics

SANTA CLARA, USA: Advanced Analogic Technologies Inc., an analog semiconductor company focused on powering innovative solutions in consumer, industrial, and communications markets, has introduced the AAT3698, a single input 1.6A linear charger with 28V input protection and 50mA low dropout (LDO) to manage the charging, sequencing and protection of Lithium (Li)-Ion and Lithium Polymer-powered portable devices.

Targeting portable electronic devices including cellular phones, GPS navigation systems, portable media players and general hand-held consumer devices, the AAT3698 incorporates key safety features that adjust for excessive temperature or voltage, up to 28V, to avoid over-charging or other damage to the battery during charging.

"Lithium-Ion and Lithium-Polymer batteries are nearly synonymous with today's portable electronic devices," said Roger Smullen, product marketing manager at AnalogicTech.

"A device's ability to maximize its battery life and charging speed, while minimizing power loss is a critical consideration to its acceptance in the consumer marketplace. The AAT3698 is able to deliver these performance characteristics through USB connectivity or an AC adapter, giving designers even more options to enable broad adoption."

Part of AnalogicTech's Battery Manager Total Power Management IC (TPMIC) product family, the AAT3698 is a linear battery charger IC developed for single-cell Lithium (Li)-Ion and Li-Polymer batteries. Able to manage input voltage of up to 7V the IC integrates many features to increase design flexibility and facilitate design-in.

Among these features are a 5V/50mA LDO that can provide additional power to an external device such as a radio in a wireless-communication product. This regulator is enabled at all times regardless of the status of the charger and is protected by an over-voltage protection (OVP) switch.

The AAT3698 is a small standalone charger solution that requires only 2 resistors and 4 small capacitors to operate and comes in a small, lead-free 14-pin 4 mm x 4 mm thin quad flat no-lead (TQFN) package. The AAT3698 precisely regulates battery voltage for Li-Ion/Polymer battery cells through a low RDS (ON) switch after it has reached 4.2V. The charging current can be set by an external resistor up to 1.6A.

Besides the IC's built-in OVP circuit that helps prevent damage to the battery and the charging circuitry, other fault conditions are monitored in real time. In case of an over-current, battery over-voltage, short circuit, or over-temperature failure, the device will automatically shut down, thereby protecting the charging device, control system, and the battery under charge.

A status monitoring output pin (STAT) is provided to indicate charging activity. This open drain output pin can be used to drive an external LED as a charging indicator. When the battery voltage has reached the constant voltage level, the AAT3698 has two charge termination and recharge modes--- one controlled by the charger (AAT3698-1) and one where charge termination and recharge is managed by the host (AAT3698-2).