Overview

In addition to knowing general system issues, the SiP designer must be capable of resolving circuit details to meet the system requirements. Discrete components behave vastly differently than ideal theory predicts as frequencies increase. This difference is mainly due to parasitic or stray inductance, capacitance, and resistance in the mechanical construction of the component. This construction and behavior are discussed in this chapter with emphasis on inductors, since discrete inductors are more costly than discrete capacitors. Embedding inductors will yield more of a cost impact on the module than embedding capacitors and resistors.

The SiP designer requires vast modeling skills. Wirebond and interconnect models are typically performed with an electromagnetic 3D simulator. A model extraction utility may be used to generate a simplified linear model of these 3D electromagnetic simulation results. Most specific circuit designs are done with a linear simulator first and then proceed to an electromagnetic 2.5D simulator if needed. System issues are typically diagnosed with either custom spreadsheets or system simulators. A good system simulator should be able to easily incorporate circuit design results within the system simulator as separate circuit block designs are completed. On the other hand, VCO and power control loops may require envelope simulators, which are not offered by many RRF simulation software providers. Most providers do offer nonlinear analysis, but it is rarely used unless the SiP designers are at device manufacturers that develop their own nonlinear device models. SiP designers at a packaging manufacturer are typically not privy to device...