利用轉換器回授方式於5.8-GHz之CMOS低雜訊放大器

Abstract

In this paper, we present the whole design of a low noise amplifier in a 0.18μm CMOS process for 5.8 GHz wireless local area network application. To operate at 1 V low-voltage supply and 16 mW low-power consumption, transformer-feedback technique is employed here to neutralize the gate-drain overlap-capacitance of a MOSFET, i.e., Miller effect. First in this paper, the design approach of the transformer-feedback LNA is described in detail. Second, differentially monolithic-transformer structure is designed, analyzed, and its lumped-element equivalent circuit model is also proposed to characterize its performance. Then, parasitic effect of lossy monolithic-inductor and transformer were studied and included in the simulation of the whole practical design. Their influences on noise and power gain are discussed and then circuit optimization is performed. The simulation results of final design show that the real design can achieve a power gain of 13.2 dB, noise figure of 2.7dB, input return loss of -22 .7 dB, output return loss of -13.8 dB, reverse isolation of -38 .3 dB, and input third-order intercept-point of 6.8 dBm. Finally, the low voltage-supply LNA based on transformer-feedback technique and internal input-matching circuit is layouted and measurement set-up is discussed for verification.