Analysis and Design of Ultra-Wideband Low-Noise Amplifier With Input/Output Bandwidth Optimization and Single-Ended/Differential-Input Reconfigurability

A CMOS low-noise amplifier (LNA) for ultrawideband universal radio is presented. Based on capacitive cross-coupled dual-g_m-enhancement topology, the circuit topology could be reconfigured as different versions for single-ended or differential inputs. One possible input/output resonant scheme is analyzed and may help the LNA to exhibit input matching, low noise, and flat gain in an ultra-wide frequency band with relatively low power consumption. Both a differential-input-differential-output and a single-ended-input-differential-output version are fabricated in 0.18 μm CMOS technology. The differential-input version achieves an 11-14 dB S₂₁, ≤ -9 dBS₁₁ within 1.4-11.4 GHz, and a minimum noise figure of 3.9 dB; the single-ended-input version achieves a 5-8 dB S₂₁, ≤ -10 dBS₁₁ among 2.4-11.7 GHz, and a minimum noise figure of 6.3 dB.