A 5.5-GHz low noise amplifier in SiGe BiCMOS

A 5.5-GHz low-noise amplifier (LNA) with switchable gain and temperature and supply-voltage compensation implemented in SiGe BiCMOS is presented. The LNA gain (S
21
) and 50-Ω noise figure are 14.1 dB and 2.4 dB, respectively, at 25°C. An on-chip proportional-to-absolute temperature (PTAT) current reference reduces the variation in S
21
and NF
50Ω
to 0.35 dB and 0.5 dB, respectively, from 0 to 100°C. The input third-order intermodulation intercept is +1.4 dBm. The circuit consumes 4.7 mA total current from a 2.5-V supply.