Design of Subsystem Module Package for Power Distribution Network

The application processor (AP) in mobile devices requires a faster computing process and higher graphics acceleration for 3D and pixel density display in a small form factor. Hence, the power distribution network (PDN) between the power management integrated circuit (PMIC) and the system AP has become more important.

Furthermore, the mobile device industry demands much higher levels of integration and lower costs coupled with a growing awareness of the complete system’s configuration. A subsystem module package is similar to a board-level circuit that integrates a system function in a package beyond a System-in-Package (SiP) design. It is an advanced IC packaging solution to enhance the PDN and enable a smaller form factor.

Unlike a system-level design with a decoupling capacitor, a subsystem module package system needs to redefine the role of the capacitor and its configuration for PDN performance. Specifically, the design of form factor package should include careful consideration of optimal PDN performance and the number of components, which need to define the decoupling capacitor’s value and placement strategy for a low impedance profile with associated cost benefits.

This paper will focus on both the static case that addresses the current*resistance (IR) drop and AC analysis in the frequency domain with three specific topics. First, it will highlight the role of simulation in the subsystem module design for PDN. Second, it will compare the performance of double-sided component placement (DSCP) mother boards with the subsystem module package and then prove the advantage of the subsystem module package. Finally, it will introduce three-terminal decoupling capacitor (Decap) configurations of capacitor size, count and value for the subsystem module package to determine the optimum performance and package density based on the cost-effective model.