A compact, ESD-protected, SiGe BiCMOS LNA for ultra-wideband applications

Two 3.65-mW, ESD-protected, BiCMOS ultra-wideband low-noise amplifiers (LNAs) for operation up to 10 GHz are presented. These common-base LNAs achieve significant savings in die area over more widely used cascoded common-emitter LNAs because they do not use an LC input matching network. A design with a shunt peaked load achieves a high S₂₁ (17-19 dB) and low noise figure (NF) (4-5 dB) across the band. A resistively loaded design exhibits a lower S ₂₂ (15-16 dB) and higher NF (4.5-6 dB), but also utilizes 20% less silicon area. Both LNAs achieve a 1.5 kV ESD protection level and an acceptable S₁₁ (< -10 dB) across the band. Current source noise reduction is critical in common base topologies. Therefore, detailed noise analyses of MOS- and HBT-based current sources are provided.