Abstract: We propose a center-tapped equivalent model for center-tapped differential inductors.The single-ended and differential impedances in differential applications are derived.A 2-port S-parameter measurement with the center-tap grounded is used to extract the equivalent resistance,inductance,and Q-factor (RLQ).A multi-layer center-tapped differential inductor is implemented in a 0.35μm 1P4M RF CMOS process.The proposed model agrees well with the experimental results below the self-resonance frequency.

Key words: center-tapped differential inductor, center-tapped equivalent model, parameter extraction,S-parameter, 2-port, 两端口