A multi-constellation GNSS RF front-end with an integer-N PLL for compass and GPS applications

A multi-constellation GNSS RF front-end with an integer-N PLL has been implemented for Compass and GPS applications in a 0.35 μm SiGe BiCMOS process. A LNA in common-emitter topology with a noise figure of 1.7 dB is integrated on the chip. An inter-N PLL based frequency synthesizer is designed to generate different local oscillator (LO) signals for down-converting the received Compass/GPS signals in B1/B2/B3/L1/L1C band to an identical intermediate frequency (IF) of 46 MHz. The receiver achieves a maximum noise figure of 3.5 dB and a maximum gain of 112 dB with 70 dB dynamic range while consuming 32 mA current from a 3.3 V supply, with a die area of 3.5×3.8 mm² including ESD protection pads.