This part is a kind of semiconductor called D1858.
Function of this product has 2SD1858.
Manufacturers : ROHM Electronics
Image and pinout :
Some of the text within the PDF file :
Transistors Medium Power Transistor (32V, 1A) 2SD1664 / 2SD1858 FFeatures 1) Low VCE(sat), VCE(sat) = 0.15V (typical). (IC / IB = 500mA / 50mA) 2) Complements the 2SB1132 / 2SB1237. FStructure Epitaxial planar type NPN silicon transistor FExternal dimensions (Units: mm) FAbsolute maximum ratings (Ta = 25_C) (96-207-D12) 249 Transistors FElectrical characteristics (Ta = 25_C) 2SD1664 / 2SD1858 FPackaging specifications and hFE hFE values are classified as follows : FElectrical characteristic curves 250 Transistors 2SD1664 / 2SD1858 251 [ ... ]