Poles-zeros analysis and broadband equivalent circuit for on-chip spiral inductors

Poles and zeros of the transfer function determine the performance and the key features of the circuit network, such as phase, gain, and bandwidth. In this paper, the contribution of the poles and zeros to the transfer function has been shown. The factors i¾?p and i¾?z are proposed to account for the poles contribution to the peak and the zeros contribution to the valley of transfer function, respectively. A novel broadband equivalent circuit combining the physics-based circuit model and behavioral macro-model black-box network is proposed for accurately characterizing on-chip spiral inductors. The physics-based elements are extracted using the linear dependence of a set of characteristic functions on variables such as ω2 or other functions in a certain frequency range. The macro-model network described by rational functions is determined using vector fitting approaches. The proposed modeling method is validated by the on-chip spiral inductor fabricated with 0.13-µm SiGe BiCMOS aluminum process. Excellent agreements are obtained between the measured data and calculation for the proposed model up to 40GHz. Copyright © 2015 John Wiley & Sons, Ltd.