3~5-GHz SiGe UWB LNA Using On-Chip Transformer for Broadband Matching

A low noise amplifier (LNA) for ultra-wideband (UWB) systems operating in 3~5GHz frequency range is presented. The LNA circuit is a cascade topology with inductively degeneration transistor. A new input impedance matching network based on monolithic transformers was proposed to overcome to the problem of broadband matching without degrading the noise performance and power delivery. The LNA achieves a power gain of 13 dB with an input matching of -9dB over the band, , a -3 dB bandwidth of 2.9 - 7.8 GHz, an input IP3 of -2dBm, a minimum noise figure (NF) of 4.0 - 4.6dB across the entire bandwidth, while consuming 9 mW at 1.8V supply