In Situ Evaluation Method for On-Chip Inductors Using Oscillator Response

It is difficult to obtain the characteristics of on-chip inductors on site since conventional evaluation requires dedicated test devices. In this paper, in-situ evaluation of both inductance and resistance of on-chip inductors without dedicated test devices is proposed, where on-chip inductors are evaluated on the basis of the threshold current for oscillation and oscillation frequency without being affected by lead wires. The proposed method was verified by measurement, and it is found that the error against the evaluation result using a network analyzer is less than 3%