A single-to-differential lna using differential active inductor for GPS applications

This paper presents the design of a single-ended input, differential output low noise amplifier for GPS applications in 0.18 µm CMOS technology. This Low Noise Amplifier (LNA) is composed of a common source (CS) amplifier adopted with a common gate, common source (CGCS) balun load. Instead of spiral on-chip inductor, a differential active inductor circuit (DAI) is used as an active load of balun and also gm-boosting technique is used to decrease the noise figure (NF) of Single-to-Differential Low Noise Amplifier (S-to-D LNA). The LNA is simulated with Cadence Spectra which shows the S21 of 22.94 dB at 1.57 GHz, S11 of −13.1 dB, NFmin of 2.66 dB and power dissipation of 2.5 mw from 1.8 V dc power supply. By adding an external capacitor to the DAI circuit, it is possible to reconfigure the LNA to use in multi frequency range. For using the LNA in frequency range of 1.22 GHz, the external capacitor is set to 121 fF. The result shows the S21 of 20.4 dB, S11 of −12.4 dB and NFmin of 2.4 dB.