This part is a kind of semiconductor called C1251.

Function of this product has 2SC1251.

Manufacturers : ASI

Image and pinout :

Some of the text within the PDF file :

2SC1251 NPN SILICON RF POWER TRANSISTOR www.datasheet4u.com DESCRIPTION: The 2SC1251 is a Common Emitter Device Designed for High Linearity Class A Amplifiers up to 2.0 GHz. FEATURES INCLUDE: • Direct Replacement for NE74020 • High Gain - 10 dB min. @ 1.0 GHz • Gold Metalization PACKAGE STYLE .204 4L STUD MAXIMUM RATINGS IC VCB PDISS TJ TSTG θJC O O 300 mA 45 V 5.3W @ TC = 25 C -65 C to +200 C -65 C to +150 C 33 C/W O O O O 1 = COLLECTOR 2 & 4 = EMITTER 3 = BASE CHARACTERISTICS SYMBOL BVCEO BVCBO BVEBO hFE COB PG P1dB TC = 25 C O TEST CONDITIONS IC = 10 mA IC = 10 mA IE = 1.0 mA VCE = 5.0 V VCB = 15 V VCE = 15 V IC = 100 mA IC = 100 mA f = 1.0 MHz POUT = 0.5 W f = 1000 MHz MINIMUM TYPICAL MAXIMUM 25 45 3.0 20 200 3.0 13 +27 +29 UNITS V V V --pF dB dBm A D V A N C E D S [ ... ]

C1251 PDF Datasheet Download