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The design of a low power high gain current-reused CMOS low noise amplifier (LNA) for GPS applications employs a novel current-reused (CR) topology with three cascaded common source (CS) gain stages without increasing power dissipation. The LNA is fabricated using a 0.20 pm RF SOI CMOS process. It consumes 4.5 mA quiescent current from a 1.5 V supply. It has 26.4 dB of power gain, a 1.31 dB noise figure, -25.5 dBm PldB and -12.8 dBm IIP3 at 1.575 GHz. Input/output return loss is 15.9 dB/13.2 dB respectively.
With advances in wireless communication systems technology in recent years, many wireless electronic products such as smart phones have become more portable, power-saving, and capable of providing a greater variety of services. Low noise figure (NF), low power consumption, high gain and high linearity, i.e., third-order intercept (IP3), for RF amplifiers such as LNAs are critical requirements that are nearly impossible to satisfy simultaneously. To date, a two-pronged design strategy has been used to achieve these goals: one is to optimize for high gain and low noise but with low linearity for small signals with low interference; the other is to optimize for low gain with high linearity but with high noise for large signals with high interference.
GPS has become an indispensable function for tracking and navigation in mobile communications applications.1 The GPS market demands lower power and lower cost solutions for integrated receivers while the trend towards ultra-miniaturization requires the use of fewer, if any, external components.2 To detect weak satellite signals, a GPS receiver must have superior sensitivity.3 It is well known that the sensitivity of a receiver is determined mainly by the first amplifier, i.e., the LNA.4 This first amplifier stage should have a very low NF and high gain, thereby preventing the following stages from significantly degrading the signal-to-noise ratio.3'6-7 For that reason, previous GPS radios have been implemented in a bipolar or BiCMOS process due to its low noise characteristics.3-5 Furthermore, the GPS RF front-end module must occupy the smallest possible area for integration in a multimode environment.1 RF silicon on insulator (RF SOI) CMOS technology is now becoming an attractive RF front-end process for its low loss, low noise and high linearity.
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