A 1 mW 0.1-3 GHz Cryogenic SiGe LNA with an Average Noise Temperature of 4.6 K

A 0.1-3 GHz integrated cryogenic LNA exploiting SiGe HBT has been designed and implemented. The cryogenic performance of the HBT technology is investigated and a bias dependent small-signal noise model is extracted. An amplifier achieving a 4.6 K average noise temperature and 30.5 dB average gain over the desired frequency band is designed and measured at a physical temperature of 15 K. The amplifier consumes just 1 mW of dc power, which is about an order of magnitude lower than previous broadband SiGe cryogenic LNAs.