Analysis and design of a 3–26 GHz low-noise amplifier in SiGe HBT technology

The analysis and design of a wideband silicon-germanium (SiGe) heterojunction bipolar transistor (HBT) low noise amplifier (LNA) is presented. Resistive shunt-shunt feedback is employed to achieve wideband gain and matching characteristics and it is shown that the addition of small reactive elements can extend the bandwidth of the amplifier significantly. Measured data for the LNA, implemented in a 130-nm SiGe BiCMOS technology, show 9 dB gain with less than 1.0 dB variation across 3-26 GHz, and input and output return losses better than -10 dB over the entire bandwidth. The measured noise figure (NF) is less than 5 dB from 3-18 GHz and rises to only 6.5 dB at 24 GHz. In addition, the amplifier exhibits excellent linearity performance, with a input-referred third-order intercept point (IIP3) of 5.8 dBm and input-referred 1 dB compression point (P1dB) of -5.6 dBm. This SiGe amplifier occupies 0.48 mm² (including pads) and consumes 33 mW of power while operating off a 3.3 V supply.