A Broadband PVT-Insensitive All-nMOS Noise-Canceling Balun-LNA for Subgigahertz Wireless Communication Applications

Abstract

A broadband process, voltage, and temperature (PVT)-insensitive noise-canceling balun-low-noise amplifier (LNA) was implemented in the 0.13-μm CMOS process for subgigahertz wireless communication applications. The proposed LNA is based on the traditional common-gate common-source (CGCS) balun-LNA topology, and it adopts the diode-connected loads to reduce the noise contribution originated from CGCS transistors and enhance the linearity due to post linearization. The auxiliary common-source (CS) amplifier with a diode-connected is added to reduce the overall noise figure (NF) of the LNA by sharing an input signal with CGCS transistors and applying its output signal to the diode-connected load of CS transistor. Because the voltage gain of the LNA is determined by the transconductance (g <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m</sub> ) ratio of the same types of nMOS transistors, its power gain (S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">21</sub> ) and NF are quite roust over PVT variations. In experiments, it showed S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">21</sub> of 14 dB and NF of 4 dB with an input return loss (S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> ) of greater than 10 dB at 450 MHz. Concerning voltage variation (1.08-1.32 V) and temperature variation (-20 °C ~ +80 °C), the worst variations in S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">21</sub> and NF were approximately 1.4 and 1.1 dB, respectively.