The package bandwidth limitation of high speed broadband products

This report investigated the electrical performance of two different bonding techniques such as wire bonding and flip chip bonding, and the performance of two different package families such as Quad Flat-Pack No Lead (QFN) and Plastic Ball Grid Array (PBGA). These two package families have played important roles on the leading edge high performance broadband products used for the blooming networking and computing market. These interconnect models were created in a commercial available Three Dimensional Electromagnetic solver and the equivalent circuits were exported into SPICE for both time domain and frequency domain circuits analysis. The bandwidth of the selected package families depends on not only the die size and lead count, but also the package lead pitch. The uniqueness of this study is that the bandwidth of the selected package families has been investigated as a function of their attributes. Several points have been observed. (1) The bandwidth decreases with the increasing lead count in all the packages. (2) The QFN works quite well in low lead count, but its performance rolls off drastically as the lead count increases. (3) The performance of a flip chip PBGA is better than that of a wire bond PBGA, and the flip chip PBGA has more available "Best Pin" than what the wire bond PBGA has. This bandwidth limitation generated in this report can be used as a reference for product group Co select a suitable package or for development group to rationalize the technology direction. The analysis techniques used here can be applied to a specific design.