Wideband LNA Employing Intrinsic Feedback and Back-Gate Resistance for Noise and Input Power Matching

This article investigates two low-noise-amplifier (LNA) topologies that provide wide input-power-matched bandwidths and low noise figures. These topologies offer the distinct advantage of eliminating the need for elaborate matching networks at the LNA input. Instead, they utilize intrinsic feedback via gate-drain networks and/or the resistance of the SOI-transistor back-gate terminal to realize the real part of the input impedance. These topologies are experimentally demonstrated with two 22-nm FDSOI LNAs. An LNA matched with the assistance of the gate-drain network exhibits bandwidth from 7.7 to 33.3 GHz, which is further improved to 6–38.7 GHz through the application of the back-gate-resistance method. The two LNAs exhibit noise-figure minima of 1.8 and 1.9 dB, maximum gains of 14.7 and 15.6 dB, and maximum IP1dBs of −9.1 and
$-\text {7.8 dBm}$
while consuming 10 and 7.8 mW of power (from 0.8- and 0.4-V supplies) and occupying 0.04 and
$\text {0.03 mm}^{2}$
of active areas, respectively.