Silicon bipolar fixed and variable gain amplifier MMICs for microwave and lightwave applications up to 6 GHz

Three MMICs for microwave applications up to 6 GHz and for digital lightwave applications up to 5 Gb/s are presented. They are: (1) a 8-dB gain, 6-GHz half-power loss, fixed-gain wideband amplifier, fabricated in modified discrete transistor process: (2) a high-gain low-noise (1.6 dB) amplifier that can also be effectively used as a transimpedance amplifier; and (3) a 3-GHz variable-gain amplifier (VGA) with a wide gain control range (50 dB), suitable for 5 Gb/s-data rates in digital lightwave systems. The circuits were fabricated using a nonpolysilicon-emitter silicon bipolar process for transistors with a gain-bandwidth product f/sub T/=10 GHz and maximum oscillation frequency f/sub max/=20 GHz. >