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

A broadband process, voltage, and temperature (PVT)-insensitive noise-canceling balun-low-noise amplifier (LNA) was implemented in the 0.13-μ m 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 (gm) ratio of the same types of nMOS transistors, its power gain (S21) and NF are quite roust over PVT variations. In experiments, it showed S21 of 14 dB and NF of 4 dB with an input return loss (S11) 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 S21 and NF were approximately 1.4 and 1.1 dB, respectively.