RF SiP technology is an enabling packaging platform for wireless communication, which is constrained by the fact that, today, SiP design is an "expert engineering" processone that is not scalable as a general design solution.
To facilitate a move to mainstream SiP implementation, an integrated, scalable SiP design solution must be developed and reference flows provided. The new solution will involve a change in design methodology for SiP products.
Supported by a new technology, the methodology will enable engineers to co-design ICs, IC packages, and the targeted PCB, from concept to production. This article describes the basic design challenges of SiP methodology and suggests a manageable, cost-effective solution.
SiP: More functionality, faster
Manufacturers of wireless communication devices are increasingly turning to SiP design to help them squeeze more functionality into less space in a competitive time frame.
One reason is that SiP implementation allows a high degree of flexibility in package architecture, particularly for RF applications. It also allows for lower power and less noise; flexibility in mixing and matching IC technologies; and, relative systems-on-chip (SoCs), SiP modules can generally be created more quickly.
However, it is SiP design's advantagethe ability to incorporate combinations of digital ICs, logic ICs, RF ICs, passive components, and mechanical partsthat creates some of its greatest challenges.
These challenges include the need for multi-technology simulation at the top-level; dedicated modeling techniques for integrated passives; and complex signal integrity and power delivery verification capabilities. The next-generation wireless systems promise to be even more complex as systems must be multi-standard and re-configurable.
RF SiP Design is an integration and implementation platform based on a single package substrate that allows the integration of digital ICs, logic IC, and RF ICs plus passive components, SAW filters, and mechanical parts. An example of a typical SiP that integrates a DSP, a CPU, and an RF IC is show in Figure 1.
Click here for Figure 1
Figure 1: RF SiP example.
In RF SiP design implementation, the package is no longer just a connectivity interposer between an IC and a board but has become the system integration vehicle and may contain many passive elements, this itself makes an RF SiP very different from a typical digital IC package or SiP.
For example, substrate interconnect/metal structures can be considered as active devices which demand careful modeling and extraction and inclusion in functional circuit simulation so that high-order effects, such as dispersion and radiation, can be understood and managed.