This part is a kind of semiconductor called APL1581.

Function of this product has DUAL INPUT LOW DROPOUT REGULATOR.

Manufacturers : ANPEC

Image and pinout :

Some of the text within the PDF file :

APL1581 DUAL INPUT LOW DROPOUT REGULATOR Features • • • • • • • • Adjustable or Fixed Output 520mV typ. Dropout at 5A in Dual Power Voltage Mode Remote Sense Pin Available 2% Accuracy Over Temperature Range Build-in Over Temperature Protection Build-in Current Limit 5 Pin TO-220 and TO-263, TO-252, SOP-8-P Packages Lead Free and Green Devices Available (RoHS Compliant) General Description The APL1581 series of high performance positive voltage regulators are designed for use in applications requiring very low dropout voltage at 5Amp. The APL1581 can provide a output voltage at the range of 1.25V to 2.55V where both 5V and 3.3V voltage supplies are available. The superior dropout characteristics result in reducing heat dissipation compared to regular LDOs. The APL1581 also [ ... ]

APL1581 PDF Datasheet Download