CMOS offset-free circuit for resonator quality factor measurement

A CMOS offset-free circuit for on-chip resonator quality factor measurement is proposed. The originality of the proposed circuit lies in its reconfigurability: a single OTA is used to perform both peak detection and comparison. By adequately designing the two configurations, the influence of the OTA´s offset on the accuracy of Q-factor measurement can be automatically cancelled. Experimental results with a discrete circuit implemented on a PCB show that the residual offset is smaller than the theoretical counting-related error and consequently does not degrade the Q measurement accuracy, which is 0.1% in this case.