A 0.0078mm2 3.4mW Wideband Positive-feedback-Based Noise-Cancelling LNA in 28nm CMOS Exploiting $\boldsymbol{G}_{\mathrm{m}}$ Boosting
Zhe Liu, Chirn Chye Boon, Chenyang Li, Kaituo Yang, Yangtao Dong, Ting Guo
Abstract
The noise figure (NF) of the low-noise amplifier (LNA), located at the forefront of wideband receivers, directly influences the total NF of the receiver. A popular approach to suppress the noise of the input transistor to decrease the LNA NF is to utilize a noise-cancelling (NC) technique, where the main amplifier provides input matching, while the auxiliary amplifier removes the noise of the main amplifier [1]. In this scenario, the common-gate (CG) common-source (CS) NC LNA has been widely investigated because it features simultaneous noise and distortion cancellation. To achieve a NF of 3dB, the CG-CS LNA in [2] consumes 15.4mA. By employing the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$g_{m}$</tex> -boosting technique, a NF of 3.5dB is achieved in [3] while consuming 7.5mA. Benefiting from the current reuse technique, the current dissipation in [4] is reduced to 4.5mA with a NF of 2.09dB. For these reported works, the noise contribution of the auxiliary amplifier dominates the NF. However, the noise factor contributed by the auxiliary amplifier is inversely proportional to its transconductance <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$(g_{m})$</tex> ; hence, the noise contribution of the auxiliary amplifier can only be reduced by increasing <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$g_{m}$</tex> at the cost of current dissipation, rendering the NC LNA a power-hungry component of a wideband receiver.