Electronic Design

Battery-Charger IC Works From Any Source

Specially designed to optimize battery charging from any power source, including the USB and other current-limited sources, the SMB138 is the most complete and flexible charging solution for the latest mobile devices, according to its manufacturer, Summit Microelectronics. The highly integrated device uses a 3-MHz switch-mode converter at its core. The charger output rating is up to 1.25 A with over 90% typical efficiency, maximizing charge current while minimizing power dissipation by up to 50% to 80% compared to typical linear chargers. Second-generation TurboCharge technology automatically boosts output current while precisely limiting input current for USB 2.0 compliance, delivering up to a 750-mA charger output from a 500-mA USB 2.0 port or 1.25 A from a 900-mA ac-dc adapter.

An I²C digital interface and volatile/nonvolatile programmability allow highly flexible charger parameters. The SMB138 can be "custom" programmed in manufacturing and used alone without the need for system interaction. Alternatively, users can adjust virtually all charging parameters on-the-fly through the I²C interface to optimize battery charging with software depending on system needs. Programmable parameters include: input and output current limiting, pre-charge/fast-charge/termination current settings, float voltage, pre-charge voltage threshold, and the current limit for USB On-the-Go, which is also supported. The SMB138 operates with an input range from +3.5 V to +9 V and tolerates input overvoltage up to +16 V (non-operating). The operating temperature ranges from –30°C to 85°C. The device comes in a 2.1- by 3.15-mm 19-ball or 20-ball chip-scale package or a 5- by 5-mm 32-pad quad flat no-lead package. Both comply with the European Union’s Restrictions on Hazardous Substances.


The SMB138 is available now in production quantities.


The device costs $1.69 each in quantities of 10,000.


Visit www.summitmicro.com/prod_select/summary/SMB138/SMB138.htm.

TAGS: Mobile
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