This part is a kind of semiconductor called P123.

Function of this product has PATENTED GOLD METALLIZED SILICON GATE ENHANCEMENT MODE RF POWER VDMOS TRANSISTOR.

Manufacturers : Polyfet RF Devices

Image and pinout :

Some of the text within the PDF file :

polyfet rf devices General Description Silicon VDMOS and LDMOS transistors designed specifically for broadband RF applications. Suitable for Military Radios, Cellular and Paging Amplifier Base Stations, Broadcast FM/AM, MRI, Laser Driver and others. "Polyfet" process features gold metal for greatly extended lifetime. Low output capacitance and high Ft enhance broadband performance TM P123 PATENTED GOLD METALIZED SILICON GATE ENHANCEMENT MODE RF POWER VDMOS TRANSISTOR 2 Watts Single Ended Package Style SO8 HIGH EFFICIENCY, LINEAR, HIGH GAIN, LOW NOISE ABSOLUTE MAXIMUM RATINGS (TC = 25 C) Total Device Dissipation 10 Watts Junction to Case Thermal Resistance 15 o C/W Maximum Junction Temperature 200 o C Storage Temperature DC Drain Current Drain to Gate Voltage 50 V Drain to Source Voltage [ ... ]

P123 PDF Datasheet Download