Investigation on the mutual inductance of on-chip transformers

The behavior related to mutual inductance of on-chip transformer has been discussed comprehensively in this work, the characterization includes the low and high frequency performances. At low frequency, the analytical formula is developed to predict the mutual inductance based on GMD (geometry mean distance) approach. Moreover, the corresponding equivalent circuit is proposed to describe the high frequency characteristic. Adopting the model extraction based on the proposed circuit, the behavior of mutual inductance with opposite excitation of input signal especially in high frequency can be understood completely.