The R2A20057BM lithium-ion (Li-ion) battery charge controller IC from Renesas Electronics Corp. is designed to control  mobile devices employing one cell Li-ion batteries, such as digital still cameras and smartphones. The R2A20057BM integrates a step-down DC-DC converter and supports 2 A large-current charging in very small package in the world's smallest class.

As digital still cameras, smartphones and other mobile devices gain higher levels of functionality, their current usage increases, requiring bigger capacity of Li-ion batteries, and larger currents for charging these batteries. However, systems for large-current charging employ multiple power metal-oxide-semiconductor field-effect transistors (MOSFETs) and discrete passive components, and large-scale heat emission structure under large-current handling, while they need mounting area compactness especially for mobile devices.

To solve these problems, the new R2A20057BM substantially reduces the mountingarea by integrating multiple power MOSFETs and charging circuits in a single chip, using a wafer-level package, a packaging technology that can also supply large amounts of current due to reduced package resistance. In addition, itincorporates a highly efficient on-chip step-down DC-DC converter to realize large-current charging while keeping heat generation to a minimum.

The use of a very finer high-voltage-tolerance wafer process and wafer-level package (WL-BGA, 25-pin, 0.4 mm pitch) allows Renesas to achieve a compact chip size in the world's smallest class of only 2.47 mm × 2.47 mm. In addition, the integrated 2 MHz high-frequency step-down DC-DC converter enables a use of compact multi-layer-chip inductors as the external devices. The 25 V on-chip, high-input voltage-tolerance enables a built-in overvoltage protection circuit and eliminates an external overvoltage protection circuit, contributing to a substantial reduction in the mounting area.

Samples of the R2A20057BM battery charge controller IC are available now, priced at US$4.0 per unit.