Sub-2.5 dB noise figure GaAs HBT direct-coupled LNAs for high volume commercial applications to 6 GHz

Abstract

A direct-coupled low noise amplifier with less than 2.5 dB noise figure up to 4.3 GHz has been demonstrated using 2 /spl mu/m emitter-width GaAs HBTs. A noise figure of 2.2-2.5 dB and a nominal gain of 33 dB has been achieved with a 4.3 GHz 3-dB bandwidth. A low power consumption version obtained a noise figure of 3.0-3.1 dB, a gain of 24 dB, and a bandwidth of 4.5 GHz while consuming only 64 mW of dc power through a 5 volt supply. The HBT amplifier chips are miniature in size, 0.27/spl times/0.3 mm/sup 2/, and can yield over 25000 die per 3-inch GaAs wafer at a cost well under $1 per die, making them suitable for high volume low cost commercial applications. These amplifiers benchmark the lowest noise figures reported for an HBT amplifier and are comparable to commercially available state-of-the-art silicon bipolar LNAs, but with more than four times the frequency bandwidth performance.