This part is a kind of semiconductor called BLF177.

Function of this product has HF/VHF power MOS transistor.

Manufacturers : NXP

Image and pinout :

Some of the text within the PDF file :

DISCRETE SEMICONDUCTORS DATA SHEET BLF177 HF/VHF power MOS transistor Product specification File under Discrete Semiconductors, SC08a September 1992 Philips Semiconductors Product specification HF/VHF power MOS transistor FEATURES • High power gain • Low intermodulation distortion • Easy power control • Good thermal stability • Withstands full load mismatch. andbook, halfpage 1 BLF177 PIN CONFIGURATION 4 d DESCRIPTION Silicon N-channel enhancement mode vertical D-MOS transistor designed for industrial and military applications in the HF/VHF frequency range. The transistor is encapsulated in a 4-lead, SOT121 flange envelope, with a ceramic cap. All leads are isolated from the flange. A marking code, showing gate-source voltage (VGS) information is provided for matched [ ... ]

BLF177 PDF Datasheet Download