The Hybrid Coplanar Transmission Line Design and Simulation for an Ultra Small Solid State Drive with Massive Storage Capacity Used in Mobile Device

摘要

This paper analyzes the electrical design alternative for the challenges of the system in package (SIP). Due to the physical limitation of the size to meet the industrial requirements, the substrate of SiP is limited with layer count and limited space between signal traces. The transmission need to use the unconnected power nets as its reference planes and make it function as ground planes for transmission line signal integrity to reduce the layer count. This idea is realized by using electrical power nets being coupled to ground filling between traces in the routing layer and having connections between ground fillings along the transmission line routing direction as a closed ground return path. Since these connected ground fillings along the traces looks like coplanar transmission line, we call these type of transmission line as hybrid coplanar transmission line. The signal propagation on the hybrid coplanar transmission line is simulated and correlated with electrical measurements in the lab. By using the hybrid coplanar transmission line, we can reduce the layer count for reducing the substrate thickness and maintain the signal integrity performance for the high-speed signal propagating performance in high-density Solid State Drive (SSD) that is manufactured by Intel.