This part is a kind of semiconductor called R5478N248CD.

Function of this product has Li-ION/POLYMER 1CELL PROTECTOR.

Manufacturers : RICOH

Image and pinout :

Some of the text within the PDF file :

Li-ION/POLYMER 1CELL PROTECTOR R5475N/R5478N SERIES No. EA-291-121009 OUTLINE The R5475N/R5478Nxxxxx Series are high voltage CMOS-based protection ICs for over-charge/discharge of rechargeable one-cell Lithium-ion (Li+) / Lithium polymer excess load current, further include a short circuit protector for preventing large external short circuit current and Excess discharge-current. Each of these ICs is composed of three voltage detectors, a reference unit, a delay circuit, a short circuit protector, an oscillator, a counter, and a logic circuit. When the over-charge voltage crosses the detector threshold from a low value to a high value, the output of COUT pin switches to low level after internal fixed delay time. The conditions to release over-charge detector are different by mask option [ ... ]

R5478N248CD PDF Datasheet Download