This part is a kind of semiconductor called BCP53-16.

Function of this product has PNP Silicon AF Transistors.

Manufacturers : Infineon Technologies AG

Image and pinout :

Some of the text within the PDF file :

BCP51...BCP53 PNP Silicon AF Transistors
For AF driver and output stages
High collector current
Low collector-emitter saturation voltage
Complementary types: BCP54...BCP56 (NPN) 4 3 2 1 VPS05163 Type BCP51 BCP51-10 BCP51-16 BCP52 BCP52-10 BCP52-16 BCP53 BCP53-10 BCP53-16 Marking BCP 51 1=B BCP 51-10 1 = B BCP 51-16 1 = B BCP 52 1=B BCP 52-10 1 = B BCP 52-16 1 = B BCP 53 1=B BCP 53-10 1 = B BCP 53-16 1 = B Pin Configuration 2=C 2=C 2=C 2=C 2=C 2=C 2=C 2=C 2=C 3=E 3=E 3=E 3=E 3=E 3=E 3=E 3=E 3=E 4=C 4=C 4=C 4=C 4=C 4=C 4=C 4=C 4=C Package SOT223 SOT223 SOT223 SOT223 SOT223 SOT223 SOT223 SOT223 SOT223 1 Nov-29-2001 BCP51...BCP53 Maximum Ratings Parameter Collector-emitter voltage Collector-emitter voltage RBE
1k Collector-base voltage Emitter-base voltage Symbol VCEO VCE [ ... ]

BCP53-16 PDF Datasheet Download