This part is a kind of semiconductor called BA41W12ST.
Function of this product has Dual Output Voltage Regulator with Power Saving.
Manufacturers : Rohm
Image and pinout :
Some of the text within the PDF file :
Regulator ICs Dual output voltage regulator with power saving BA41W12ST The BA41W12ST is a general-purpose power supply with two outputs : 8V, 1A and 5V, 500mA. The IC is available in a compact TO220FP-5 package. The outputs can be turned off during the power saving state with a built-in switch. Also built in the IC are an overcurrent protection circuit, an overvoltage protection circuit, and a thermal shutdown circuit. FApplications Car audio systems, VCRs, facsimiles, air conditioners, and other household and industrial equipment FFeatures 1) Minimum I / O voltage differential is 0.5V or less. 2) Built-in protection circuits against overcurrent, overvoltage, and overheat. FBlock diagram 3) Available in a compact TO220FP-5 package (pins are bendable). 4) Zero power saving current. (Typ. [ ... ]