This paper reports on a S-, C-band low-noise power amplifier (LNPA) which achieves a sub-0.2 dB noise figure (NF) over a multi-octave band and a saturated output power (Psat) of 2 W at a cool temperature of -30degC . The GaN MMIC is based on a 0.2 mum AlGaN/GaN-SiC HEMT technology with an fT ~ 75 GHz. At a cool temperature of -30degC and a power bias of 15 V-400 mA, the MMIC achieves 0.25-0.45 dB average NF over a 2-8 GHz band and a linear P1dB of 32.8 dBm ( ~ 2 W) with 25% power-added efficiency (PAE). At a medium bias of 12 V-200 mA, the amplifier achieves 0.1-0.2 dB average NF across the same band and a P1dB of 32.2 dBm (1.66 W) with 35% PAE. The corresponding saturated output power is greater than 2 W. At a low noise bias of 5 V-200 mA, a remarkable 0.05-0.15 dB average NF is achieved with a P1dB > 24 dBm and PAE ~ 33%. These results are believed to be the lowest NF ever reported for a multi-octave fully matched MMIC amplifier capable of > 2 W of output power.