A 1.4 V osicllator for CMOS capacitive sensor interfaces

摘要

A novel CMOS oscillator to be used in integrated capacitive sensor interfaces is here presented. The proposed topology is based on a hysteresis comparator adapted for low-voltage single supplies, the minimum being 1.2 V.A 1.4-V design with an overall power consmption of only 23 #mu# W is given. A capacitive range of 10 fF-100 pF, to which corresponds a frequency span of about 300 Hz-3MHz, has been considered. The circuit shows low sensitivity to supply discharges and good output linearity for tem,perature variations. These characteristics have been verified to be better than the corresponding performance of a typical solution presented in literature.