lowpowerZONE Products for the week of August 16, 2010

Advanced Analogic Technologies Says…

AAT3698: Charger IC Improves Battery Performance in Today’s Portable Electronics

Advanced Analogic Technologies, Inc. (AnalogicTech), an analog semiconductor company focused on powering innovative solutions in consumer, industrial, and communications markets, 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.”

EN-Genius Says…

The AAT3698 is a Li+ battery charger for single 4.2 V cells in two versions, the AAT3698-1 and the AAT3698-2. It uses the now conventional pre-conditioning, constant current, constant voltage charge cycle and also provides an always-on 5 V 50 mA LDO (with overvoltage protection).

The charging current is programmable by a single external resistor for up to 1.6 A or as low as 50 mA. A fast turn-off overvoltage protection is included as well as undervoltage lockout, power OK and charge status monitoring (ignore the wrong direction of the emission arrows on the data sheet front-page block!) There is also reverse current blocking, a battery absent detection pin, and thermal shutdown protection. The -1 version also includes automatic termination and recharge sequencing.

The AAT3698 can use an input rail of between 3 V and 7 V with an overvoltage protection range up to 28 V. The input and output capacitors can be as low as 1 µF (ceramics) and only a couple of additional external resistors are required. The operating current is less than 0.5 mA.

This is a nicely complete battery charger for single Li+ (Lithium-ion and Lithium-polymer) cells with very few external components needed and, therefore, offering a low real estate profile. The addition of the always-on LDO is a nice touch. The maximum input voltage of 7 V is a limitation for low-cost wall-wort applications but is ideally suited for USB. With a maximum charge current of 1.6 A this is one of the highest that is available in the industry in what is a very readily-accepted package. Why then is the part so underpriced? We would have expected the AAT3698 to command a 1000-piece list price of between $1.45 to $1.75.

The AAT3698 is in production in thermally-enhanced TDFN-14 and is priced at $0.52 in 1000-piece lots. Evaluation boards are available.

Data Sheet