Maxim Integrated Products introduces the MAX8730, a integrated battery-charger IC. The device charges three to four lithium-ion (Li+) cells in series at charge currents greater than 3.5A. Analog inputs control input current limit, charge current, and voltage. An integrated 3.3V LDO supplies over 20mA current to any external circuitry or ICs, such as a keyboard controller. Three monitoring outputs simplify design, and save external component cost and board space. Two analog outputs are available for charge current and input current; a digital output is used to detect AC-adapter presence. The MAX8730 provides 0.5% accurate battery-voltage regulation, which increases battery capacity and minimizes charging time. The device can be hardwired or controlled by a microprocessor to set the charging current or voltage. Based on the presence or absence of an AC adapter, the MAX8730 uses two p-channel MOSFETs to automatically select the appropriate source for powering the system. The device features AC-adapter current limiting. The IC monitors the current drawn from the adapter and adjusts the charge current so that supplying the system load and the charger simultaneously does not overload the adapter. This feature enables system operation with lower cost AC adapters.

The MAX8730 is packaged in a 28-pin QFN (5mm x 5mm), and is specified for the extended industrial temperature range (-40°C to +85°C). The MAX8730 is also available in a lead-free package. Prices start at $5.04 (1000-up, FOB USA).