This part is a kind of semiconductor called MRF581.

Function of this product has RF and Microwave Discrete Low Power Power Transistors.

Manufacturers : Advanced Power Technology

Image and pinout :

Some of the text within the PDF file :

140 COMMERCE DRIVE MONTGOMERYVILLE, PA 18936-1013 PHONE: (215) 631-9840 FAX: (215) 631-9855 MRF581/MRF581A RF & MICROWAVE DISCRETE LOW POWER TRANSISTORS Features • • • • Low Noise - 2.5 dB @ 500 MHZ Gain at Optimum Noise Figure = 15.5 dB @ 500 MHz Ftau - 5.0 GHz @ 10v, 75mA Cost Effective MacroX Package Macro X DESCRIPTION: Designed for high current, low power, low noise, amplifiers up to 1.0 GHz. ABSOLUTE MAXIMUM RATINGS (Tcase = 25°C) Symbol VCEO VCBO VEBO IC Parameter Collector-Emitter Voltage Collector-Base Voltage Emitter-Base Voltage Collector Current MRF581 18 30 2.5 200 MRF581A 15 Unit Vdc Vdc Vdc mA Thermal Data P D D Total Device Dissipation @ TC = 50º C Derate above 50º C Total Device Dissipation @ TC = 25º C Derate above 25º C Storage Junction Temperature Ran [ ... ]

MRF581 PDF Datasheet Download