A low power high gain gain-controlled LNAC＋mixer for GNSS receivers

A low power high gain gain-controlled LNAC+mixer for GNSS receivers is reported. The high gain LNA is realized with a current source load.Its gain-controlled ability is achieved using a programmable bias circuit. Taking advantage of the high gain LNA, a high noise figure passive mixer is adopted. With the passive mixer, low power consumption and high voltage gain of the LNACmixer are achieved. To fully investigate the performance of this circuit, comparisons between a conventional LNAC+mixer, a previous low power LNAC+mixer, and the proposed LNAC+mixer are presented. The circuit is implemented in 0.18 m mixed-signal CMOS technology. A 3.8 dB noise figure, an overall 45 dB converge gain and a 10 dB controlled gain range of the two stages are measured. The chip occupies 0.24 mm2and consumes 2 mA current under 1.8 V supply.