Low power SAW-based oscillator for an implantable multisensor microsystem

The architecture of a low-power implantable multisensor microsystem dedicated to in vivo monitoring of biological parameters is presented. Low-power RF circuit techniques based on the g(m)/I-d methodology, used to design the communication module of this biotelemetry microsystem, are discussed. A derivation of the optimal operating point of a Surface-Acoustic Wave (SAW) oscillator is presented based on the resonator's frequency response. The low-power oscillator, implemented in a 90-nm CMOS process, is presented to illustrate the design techniques used. The oscillator draws 320 mu A from a 1-V supply and the amplitude of oscillations is 200 mV.