Parasitic-Aware Analytical Modeling of Fully Integrated Switchable Narrow-Band CMOS Low Noise Amplifiers

In this paper, we present an accurate and efficient analytical modeling methodology for fully integrated switchable narrow-band CMOS low noise amplifiers (LNA) in multi-band wireless systems. We employ this modeling methodology to choose the most suitable values for specific passive elements. These passive elements were chosen based on sensitivity analysis study to tune the circuit over the different frequency bands. In order to accurately predict both the impedance matching and the noise figure, the modeling methodology captures the impact of parasitics on passive components, ESD-protection structures, and devices. Our design example is a tri-band switchable narrow-band LNA that operates at 900MHz, 2.4GHz and 5.2GHz, representing the GSM, Bluetooth and WLAN standards. Based on our sensitivity analysis, we defined the most effective passive elements that can be used to tune the circuit over the three frequency bands while achieving the required performance and minimizing the number of the switchable elements. Simulation results demonstrate that our automated design methodology achieves the required LNA specifications over the tri-band while providing five orders of magnitude improvement in design space exploration speed over circuit-level based methodology.