A 1.2-mW CMOS frequency synthesizer with fully-integrated LC VCO for 400-MHz medical implantable transceivers

Abstract

An ultra low-power frequency synthesizer for 400-MHz medical implantable transceivers was designed and fabricated in a 0.13-mum CMOS technology. The circuit is implemented by means of an integer-N phase-locked loop, which features a fully-integrated LC VCO and 160/480-kHz programmable channel steps. The frequency synthesizer exhibits a phase noise better than -96 dBc/Hz at 100-kHz offset frequency for all the supported channels. The measured settling time is around 500 muS and the reference spurs are lower than -52 dBc. The power consumption of the frequency synthesizer is only 1.2 mW from a 1.2-V supply.