Packaging effects on a CMOS low-noise amplifier: Flip-chip versus wirebond

A model-based study is presented to compare the effects between flip-chip and wirebond package on a low-noise amplifier (LNA) in a 2.4 GHz CMOS wireless local area network (WLAN) receiver. To construct the package electrical models, specific modeling dies are designed to help extract the equivalent-circuit parameters from measured S-parameters for chip-package interconnects. Furthermore, the ground proximity effects on on-chip spiral inductors in a flip-chip package are also modeled in this study. Excellent agreement between modeling and measurement is obtained up to 20 GHz for a 64-pin flip-chip ball grid array (FCBGA) package and a 64-pin wirebond quad flat nonlead (QFN) package. In practical applications, the established package models are used to predict the RF specifications of a 2.4 GHz CMOS LNA when packaged in the above two packages. Consequently, chip-package co-simulation achieves a good agreement with measurement, and thus can persuasively account for the effects caused by the two different packages.