Many emerging portable applications — such as Bluetooth headsets, high-end portable music players, and compact digital cameras — use extremely small batteries that require tiny low-power battery chargers. By offering a simple, complete USB/AC adapter battery charger in an ultra-small 2.0×2.1mm package, AnalogicTech¹s AAT3681 allows designers to meet tight space constraints, reduce development time, and quickly get their product to market.
The AAT3681 integrates a charging device and reverse blocking diode to precisely regulate battery charge voltage and current for 4.2V Lithium-ion/polymer battery cells. It operates from a DC power source or USB port across a 4.0V to 6.5V input voltage range.
The device¹s adapter/USB charge input constant current level can be programmed up to 300mA for rapid charging. The AAT3681 includes a status monitor output pin capable of directly driving an external LED to indicate battery charge state. Other than optional decoupling capacitors, the device requires only a single external resistor for complete functionality.
Protection circuits in the AAT3681 continuously monitor the charge state for fault conditions. If an over-voltage, short-circuit, or over-temperaturecondition occurs, these circuits automatically shut down the AAT3681 to protect the charging device, control system, and battery under charge.
The AAT3681 is AnalogicTech¹s first production device developed in its proprietary new ModularBCD process technology. This new process differs from conventional BCD technologies by using a low-temperature, CMOS-like flow capable of achieving high yields while ensuring device performance and electrical isolation. By allowing AnalogicTech¹s designers to easily add or remove modules and devices with different supply voltages, this highly modular process vastly simplifies analogue and mixed-signal circuit reuse.
The AAT3681 battery charger IC is a standalone product and is a key ModularBCD building block for upward integration into power systems-on-chip. Specified over the -40 to +85 degrees C temperature range, the AAT3681 is available in a Pb-free, 8-pin 2.0×2.1mm SC70JW package.