Power minimization of a 433-MHz LC VCO for an implantable neural recording system

This paper presents a new random-search based integrated inductor optimization algorithm. The algorithm provides the designer with valuable information about design tradeoffs. It is used to design an inductor to minimize power dissipation in an LC VCO. The measured results show that a 53:1 power savings can be achieved over VCOs using inductors optimized only for maximum Q. Six 433-MHz VCOs were fabricated and measured. The VCO using the optimal inductor design has a measured minimum power dissipation of 1.2 mW in a 0.5-mum three-metal CMOS process