An improved wideband equivalent circuit model for integrated spiral inductors in CMOS technology

摘要

This paper presents an improved wideband single-pi model for on-chip spiral inductors based on the independent tested ground PADs (ITGPs). For the ITGP, the input and output ground PADs are not connected together that introduces potential difference between the input and output ground PADs. However, the conventional inductor models are suitable for the ground PADs being connected together; they usually ignore the input and output potential difference and failed to achieve high model accuracy for the ITGP structure. To develop an accurate model for ITGP, the potential difference between input and output ground PADs is analyzed in this paper, and then the lumped-parameter resistor-capacitor network is used to characterize it. To validate the proposed model, the test structures were fabricated by 0.18-mu m CMOS technology and measured up to 67 GHz. Compared with the conventional model, the calculation results of the proposed model agree the measurement results better. Furthermore, the root mean square errors (RMSEs) of proposed model are less than 0.025.